Is Anyone Concerned About This?

I am a complete amateur trying to learn.

What I think I know so far is that COVID made available entry points for many new investors.

Since the rebound, the overall trading volume has been steadily decreasing.

This makes me think that more and more of those new investors are making their way out of the market as a whole.

If less investors are in the market, how is the average share value continuing to increase?

Is this creating a bubble? Whatever "bubble" means

Im concerned, something is not adding up.