In the US, a postdoc at a top CS school makes like $60-80k and works 60-80hrs a week, whereas a new grad of the same caliber with just a bachelors (think top 10% of graduating class) can reasonably expect to make >$200k working 40 hours a week at a FAANG. Meanwhile, Research Scientist roles (the common alternative to doing a postdoc in CS) recently cracked $400k starting. These are numbers I have personally experienced. (Verifiable on aipaygrad.es and levels.fyi).

CS is certainly an outlier in terms of salaries, but ANY person capable of landing a postdoc in a STEM field at a competitive school in the US is capable of figuring out a way to get a job as a software engineer in Big Tech (the grind of leet code is nothing compared to the grind of doing a PhD, full stop). This is why >60% of PhD grads in CS across top schools are ending up in industry, and I knew a TON of PhDs from physics, math, chemistry, etc. who left research immediately after graduating and are now SWE.