I don't know about all time highs but definitely stagnation, similar to what Japan FED/Gov is doing, they just buy enough to keep the markets from falling and I think that is what the USA FED/Gov will do.

The FED is already kind of indirectly buying stocks by giving unlimited zero interest loans to Market Makers (big financial institutions who give liquidity to the stock market, they buy/sell stocks all day long every day), they can use that money from the FED to buy/sell stocks if they choose to, and my guess is they most likely will buy as much as possible to keep stock prices from falling. When the market makers run out of money that is when the stock market comes crashing down, and my guess is the FED/Gov will never allow that to happen. https://ftalphaville.ft.com/2020/03/25/1585143723000/When-central-banks-take-over-securities-markets/

The biggest issue is the incompetence of the people in charge, they do not understand that wealth inequality is the destroyer of economic systems. When new money is printed into the system eventually that money always ends up in the hands of the richest minority which eventually leads to hyper inflation or revolution.
https://en.wikipedia.org/wiki/French_Revolution
It is the job of the Gov to make sure the currency that is created within its economic system is distributed as evenly as possible. Because an economic system works best when the majority of the population has money to spend into that economy, so the money can continue to move in a circle. When you reach a point when the majority of the population are not spending enough money because they are not earning enough/dont have enough, that is when shit starts going down hill real quick.