Obviously the forces at play are quite complicated, but it’s my belief that this is driving a good part of the rise. Who wants cash when the Fed is printing $trillions? Companies can raise their prices to keep their costs at the same fraction of revenue, so in the current environment of loose money it seems a sounder investment to many, especially if the government eventually continues the direct-to-citizen stimulus.
This is not financial advice etc.
They do say crisis is an accelerator of the rise and fall of super powers!
The hardest hit businesses (retail, restaurants, service) were small parts of the S&P500 because they usually don't have the economies of scale that tech has, and therefore don't produce the mega-caps that dominate the S&P500.
there are equal weighted index that trade - it's not nearly as recovered as the market cap weighted one but recovered significantly nonetheless. energy, transports, utilities, and certain retail companies have been doing well.