I know a professor who claims he was hired because he was, in his words, "better than everyone else." But isn't it possible that one person on the hiring committee thought he was the best applicant, another person thought someone else was the best applicant and that he wasn't even close, and a third person thought a third applicant was the best? It seems hard to say that someone on the hiring commitee was wrong and that actually the person who got the job offer was unanimously the best.
In actuality, in a pool of applicants there is a mix of attributes with some stronger in some areas and weaker in others. A committee will match those strengths and weaknesses against the requirements of a job.
The sorting isn't a consistent linear scale and it is even possible that a candidate who wasn't "best" on any criteria but had a mix of attributes that was considered most appropriate by the committee will get the job.
From the person's own standpoint, however, it is good to feel proud of yourself when you get a desired job. Saying you were the best is harmless enough on its own. Being arrogant, however, is less welcome.
"Better than everyone else" is true in the sense that the committee treated them the best fit for the position overall, not on every criteria.
What the hiring committee decided was that the successful applicant was the best suited of those in the applicant pool for that particular job. For a position that's primarily or wholly teaching, the "best" researcher isn't necessarily the best suited, and vice versa. Similarly with the other axes of the decision matrix.
He may very well have been no one's first choice, but the committee members differed about first choices and he was the majority's second, or even third choice.
No, it does not make sense
... depends on the meaning of "everyone else" and depends on the meaning of "better". Maybe a more nuanced answer is that this person was judged to be the best qualified in the pool of candidates at the time the offer was made.
"everyone else" would depend on the pool of applicants. If there was only one other applicant, this person would indeed be "better than anyone else".
Additionally, "better" depends on better at what, and who does the evaluating. If a job is posted in number theory, and there is a fantastic applicant working in differential equations, the latter might be better than all those with a number theory background, but the job might still go to a number theorist. Even if the job is broadly advertised, it is quite possible that internal departmental politics is involved, because -- say -- one candidate could collaborate with a committee member, or works in the area of research of a committee member. It could be the acknowledged top candidate has an intolerable personality so the committee will overlook this "better" candidate.
Hiring someone is always a matter of compromise. While it is likely that anyone hired is well qualified, it's not clear this person is "better than anyone else".
"Best" in the eyes of an employer means a lot of things. Most affordable of the applicants. Most qualified of the applicants. Best interpersonal skills of the applicants. Best balance of competing interviewer opinions... you get the picture. But none of that has any meaning if there's someone out there who is yet more affordable, more qualified, has better interpersonal skills... and yet didn't apply.
This means your professor is both completely right and entirely wrong. He's certainly the best the department could hire of the applicants - and that means absolutely squat. Hopefully his work ethic matches his sense of self worth.
I was hired for an academic job because I impressed the dean. I didn't impress the committee beyond the minimum for the dean to hire. This turned out to be unfortunate for everyone involved, including me (at least in the short-term!) Even if everyone is impressed, it doesn't necessarily mean "best" as there are many hiring factors.
The things cited as examples in the OP's question are certainly possibly true. Sarcasm can always be a factor, determining when it is present or not is sometimes difficult also.
We always hire the best. Everyone who works here can say that they were hired because they were the best. There just might be some less flattering qualifications for "best".
They were the best that could be found, or the best who found us, given a short window of time to apply for a position, and successfully went through whatever negotiations they had in mind for compensation or other details. I mean the technical best might have been the one who decided the commute was just too long, or the one who couldn't talk us up enough in the negotiation phase, so they refused the offer, but clearly that means that they weren't the best choice.
So, the one we hired was definitely the best. At the time. Given the constraints. From that particular candidate pool. As far as we could tell in that moment.
(but still totally the best. I mean, that's why they hired me. I was the best!)
I guess, in summary, it makes sense to say it, but only in the sense that it is, after looking at all factors, a truism.
You have a causality issue (better -> hired or hired -> better), an issue in scope (who is considered?), and an issue in definition (what does "better" mean?).
You state he says:
he was hired because he was, in his words, "better than everyone else."
If someone is better than everyone else who were considered at the time, according to whatever criteria are important for the people who assessed them, it would be logical for them to be hired.
So indeed, better -> hired is quite logical.
But again, that is among the pool of applicants, and according to specific criteria, which may be "years of experience", "technical ability", "pedagogy", "number of publications", "quality of publications", "charisma", "popularity", "good looking", "cheap", "good golf buddy", "family friend", etc.
That, however, doesn't necessarily mean that him being hired means he is better than everyone else considered for all possible criteria (or even any at all that would matter to other people than those who made the decision), and much less that he is better than everyone else in the world.
So hired -> better is not necessarily true, much less if he implies that that he would be "better than everyone else in the world" (there could have been a single candidate!), or a reason completely outside of what most people would consider "better" (like a personal relationship to members of the hiring committee).
You get hired for a position if you are available and if you are the person giving the best value for the least amount of money.
Say there was just a damning report that women and ethnic minorities don’t get jobs at your university. So suddenly a black woman applying for a job becomes very valuable. Or you are supposed to work closely with an institute in France, and suddenly someone who speaks and writes French may not be the best, but very valuable. Or someone who is extremely good at their science but has a personality that makes others quit is not acceptable.