You can get significantly more than 100k in London. And even at that price, life would be quite comfortable (but of course COL is still significantly higher than many other places).
Life can be comfortable but it’s not sustainable. You can indeed be comfortable if you spend all that money on rent + lifestyle, but it’s just not enough to actually buy a property in a reasonable amount of time.
A handful of 10x devs earning 100k doesn't address the general skills shortage. In fact I'd say the overemphasis on top-tier talent in the tech sector exacerbates the problem.