It’s not regardless of government intervention. There have been numerous bailouts and interest rates deductions specifically to backstop SP500.
It is a stealth tax that targets the young (or those too poor to be beneficiaries), because leaders need to maintain purchasing power for their voters’ benefits (the vast majority going to the old) and the solvency of taxpayer funded defined benefit pensions.
Politically, asset prices will be inflated quicker than labor prices. You can use SP500 as an easy guage.
This is not sustainable forever, of course, but I would bet there are a few more decades it will work.