The thing with countering averages with anecdotes is that neither really paints a holistic picture of the demand pyramid. Back of napkin calculations say around 4% of US developers work at the FAANGMULAs, meaning that some 29 out 30 dev earnings are somewhere lower in the pay scale. But 1 out of 30
isn't an astronomically small number, so you could very well be one of those 300k TC people surrounded by others in that cohort and thinking the market is hot because professionals w/ that experience set are rare and in demand, and at the same time you could go on r/cscareerquestions and see a deluge of new grads complaining they sent out hundreds of resumes and heard nothing back.
The thing about pay that the job hoppers apparently don't take into account is that levels aren't static. Looking at my own network over the years, virtually everyone I know has been promoted or otherwise landed more senior roles, to varying degrees on both sides. You may also have noticed a significant increase of "staff engineers" in the past few years, whereas the role was basically unknown some 10 years ago. Many companies also have been quietly giving out retainer bonuses/raises to slow down attrition.
Since I started my career, I've had multiple significant compensation increases, some from raises, some from promos, one from a team move, and some from changing jobs. Increasing your experience/expertise over time can have a huge impact. Going from no-name companies to household names can have a huge impact. Relocating can have a huge impact. Negotiations (even internal ones) can have a huge impact. There isn't a one-glove-fits-all when it comes to an individual's opportunities for comp growth.
On the other hand, stagnation is very much real. There are plenty of people that do nothing in terms of career progressions, negotiations, etc and just wait for year-end bonuses to fall into their laps. It'd naive to be surprised these folks aren't keeping up pay-wise.