Senior year of Mechanical Engineering undergrad, professors would legitimately get upset with students for taking jobs in finance and consulting. They wouldn't hold back, saying quite literally "this is a waste of your education."
If they are a mechanical engineering professor at a good university, they pretty much have borne the risk of their own advice. Most people in upper-level STEM academia could easily get a higher paying job in finance/consulting and have chosen not to.
You're right it's not "a priori guaranteed," but when talking about empirical realities, what is?
A professor in a good school is like a small-business owner with a guaranteed income and a supply of free labor. In industry, the money is much better, but you're paying with your dignity and your self-respect.
Professors also likely know many other people with developed career paths that are different from their own, while a student has no career at all to draw inferences from.
People go into finance for extremely rational reasons. Getting upset at them for that is folly.
Professors aren’t rich, duh. But they’re also neither in the job market, not starting their career off. Their students need to build wealth, worry about long term earnings potential, and pay back the large student debt that they just incurred. Unless if the professor is actively planning on quoting soon, none of these are incentives that the professor are subject to personally, meaning their advice will probably underweight them.
Those who have more experience are going to be more distanced from your exact circumstances, as a function of having more experience. Advice can be useful nonetheless.
So ya agree with you about the social pressure! Let's keep it up. But we also need to find ways to align our financial incentives with social incentives!