I used to think that with every degree you get your salary goes up.
Universities produce more and more PhD's and i learned in economics 101 that once the supply is higher than the demand, the price (here salary) will drop.
Even if you get a little bump in salary, you have to take into account, that you are joining the workforce 3-4 years later and therefore "loose" those salaries.
From an economical standpoint : Is a PhD still worth doing ?
( I know, doing a PhD is not "just" about the money )
If you look at income alone, it's definitely not worth it - assuming you don't live in a country in which "Herr Doktor" is still highly regarded, and an almost must for high-end jobs in politics and business (like in Germany or Austria).
In industry, there are a few jobs (chip design for Intel or quantitative hedge funds come to mind; maybe in consulting it's a toss up; certainly there are others) where it might help. There are also jobs where it's required to have a PhD (some chemistry research, or such), or at least very beneficial. But outside these somewhat rare positions, HR will put you on a pile called "non-standard degree" which is largely ignored, and you rely on personal connections or quantitative recruiters to even get your foot in.
If you end up in academia as tenured faculty, you get a decent salary with a wide range (e.g., at the top end, Business School finance assistant professors lie around $200k at good schools, to a low end that's a fraction of that if the school or department is less wealthy, or the field less supported by industry). But if you're smart and driven enough to get there, you almost certainly could have long made partner at McKinsey by that time, where you won't go home with less than $1m.
I think the term "still" in your title is a bit off. I don't think this ever was different. You should write a Ph.D. as you're passionate about a field, look for independence, and genuinely love what you're working on. And you should be aware early, and accept, that this is not a choice made for the money.
I would say: "it depends". Basically: What is your field you want to do a PhD in? Does it complement your field of study or is it something completely new and outfits you with unique skill/expertise? Secondly: A PhD suggests -- even if it does not fit to your field of profession -- that you are capable to self-organise, to autonomously pursuit a research question and work it through. To break down a problem in abstract thesis and work problemoriented etc. These are skills that are welcome on the outer academia job market although maybe the knowledge you obtained with your PhD thesis might not be. I am a sociologist and interviewed project managers. Many told me that after my PhD I should get in touch with them, since having successfully done a PhD indicates that you can stay on a project and are disciplined to do it while 'on your own'. Third: Yes, numbers of PhD holders are increasing, however it seems that there is no saturation in the sense you proposed. Employment markets usually do not work the way you might learn in economy 101. Fourth: You said it yourself: doing a phd is not about the money and not about the fame. If your job does not require it, I would suggest, don't do it; it sets back on many dofferent accounts, like family, outer university carreer and longterm planning.
So what I am trying to tell: A scientific degree like a PhD is not so easily transformed into economic capital as one would think. Of course, it creates benefits but it also closes options down (overqualification). IMHO market principles do not work that well on it.
I have an EdD in Music Education, and now I am a software engineer in test. While I started my degree intending to be an academic in Music Education, I changed careers when I was almost done with my dissertation research, and decided to complete the degree.
The degree itself is not the deciding factor in making money, but because I was pursuing a Doctorate, tech companies were interested in interviewing me, curious about my dissertation research, and excited about the different things I pursued. Point being that you really cannot predict every aspect of life (I had no plan to leave academia), but a degree can strengthen your ability to make connections and get interviews, even if not in your chosen field. I write this to share with you my personal experience, as I can only speak for myself. Best of luck in your decision and endeavors.
This is such a hugely open ended question that I was quite tempted to vote to close it - because the core of this answer is What kind of PhD? and Compared to what?
To use two edge cases:
Even if you don't think about those edge cases, it will vary heavily by field. For example, there's good, lucrative work to be had for people with an MS in Computer Science, so a PhD might not be "cost justified". At the same time, in my own field, the work you can do with a Masters vs. a PhD are, in some cases, entirely different fields, so it becomes much more a matter of "If you want to do X, you must go get degree A", and the question of cost is more about mitigating the opportunity cost.
In more general terms though, I'd say "It depends. For technical fields maybe, for liberal arts fields probably not, if you're taking on debt almost certainly not."
Answer the following question: Do you want to become an academic?
If yes: Welcome to the club then!, you will need to do a PhD and a number of postdocs, and if you work hard at it, you will get an academic position.
If no: Simply do not do the PhD, because among other things definitely it does not help you get a better job (and money); simply because industry measure you based on your knowledge, which is determine through their interview process, and not your PhD diploma.
