Corrupt means to me that you give money (or other "services") to members of the hiring committee in order to get selected. That may happen, but I don't think that is very common in general. So lets just ignore the word corrupt.
Your last sentence is I think a better description of what you are worried about: "there exists a strong incentive for those in hiring committees to exclusively choose candidates who would support their (the hiring committee's) clique or personal goals." I take that to mean that disciplines are often divided in different "schools" and selection of candidates can depend on how well the school of the candidate fits with the school of the members of the selection committee.
This has happened and still does happen. The committee members selects their own colleagues, and you like colleagues with whom you can easily collaborate, and it is easier to collaborate if you belong to the same "school". To some extend that can be desirable: it is a legitimate goal to make a particular department a center for a particular school. However, this can also happen as a form of "intellectual laziness", i.e. not wanting to deal with people who are too different, and then it would be a bad thing. That is another reason why I object to the term "corrupt"; Whether or not it is bad depends on the goals.
However, this is a known problem and there often are policies in place to alleviate that. For example, in some German states you cannot hire a professor who was previously (and the exact definition of previously allows for loopholes...) employed by that university. What those policies are, how strong those policies are and how well they are enforced differs hugely from country to country, university to university, and department to department.
For example, you mention transparency as one such policy. However countries differ with respect to how they value privacy. That is a legitimate tradeoff. Depending on the local preferences for those two competing values, different countries should come to very different policies. That is what democracy is supposed to achieve (but not all countries are democratic).
Another complexity is that many universities are for historic reasons on a continuum between a full government agency and a private organization. This can make rules of hiring complicated as they are often some mix of rules that apply to government agencies and private organizations. That does not mean there are no rules, actually quite the opposite. But finding out what the rules are in the different countries is going to be hard. For one thing, those rules are often based on laws, and laws tend to be written in the local language, as they should. On top of the laws there are often university policies. Some of those policies will be to a larger or smaller extend coordinated across universities, others will be purely local.
In short, what you mention is often regulated to some extend, but how it is done differs a lot. Those differences are not necessarily bad (but some are).
Even shorter: it is complicated because countries differ.