>Regular mortals maximize their 401k contributions, use Backdoor Roth IRA, FSA, optimize for long-term capital gains, etc.

The only thing I would consider to be 'tax avoidance' in there is the Backdoor Roth, which is only used by a small subset of Americans because the majority don't make enough to need it. And even then the Backdoor Roth is a loophole/oversight that Congress is too cowardly to close.

The rest all serve different purposes, primarily to make necessary aspects of life (Retirement, Healthcare, etc) more affordable in our unaffordable country.