In most of the US (i.e. outside of a few large cities), $250-$300K is executive compensation, not individual contributor compensation, regardless of experience level, genius, or negotiating ability.

At $300k TC, most people in the United States could pay off their mortgage and retire after only 3-5 years of working. Is this what you mean?

I took the statement to mean that "in many/most places in the US", software engineers are earning a $300k TC by the time they reach retirement age. I still think is not correct in many/most places. It is correct only in a very small minority of places.

I was saying it was a very good (I used the term solid) salary by retirement age which I think is true. Maybe it's even exceptionally good.

I think your quoted statement is only kinda sorta true though. Assume they have $1m in the bank with no debt at age 30 now that they've retired after about 5 years and bought a $200K or so house with cash. They now have a low-risk income stream of about $50K (less than the US median income) which has to cover property taxes, maintenance, health insurance, etc. Or maybe they want nothing more than to be a ski bum or a river guide etc. for the next X decades. It's certainly possible although I doubt it's what most people able to earn that kind of money aspire to.

(If you expand it to 10 years, I'd more generally agree. If retirement from corporate life is someone's goal, that's eminently practical at that point without being at all spartan.)