There is alpha in markets. I did a lot of relatively unsophisticated SPAC relative value warrant trading during the 2020 period, and I think a big part of it is the question of scale and slippage. If you're a prop firm that makes "real money" your universe is limited by these constraints. IE "not worth the time" would be a common response to trading opportunities.

For example, there were high sophistication players in the merger/stat arb phase of the game, and they would layer out their warrants like an onion of dark liquidity (the orders were hidden/not directly listed on ARCA/etc). They were involved in just about every SPAC name out there. But when an SEC filing came out, or you learned some specifics about a certain sponsor team (maybe they have very high quality lockup partners who don't dump shares on lockup date, as shown by their last 3 SPACs), then maybe that implies a higher warrant valuation, or maybe that should be priced into the option chain. And they will happily sell to those pricing in that "hair" and sell their inventory because they don't want to deal with some 5 dollar warrant that trades 50,000 volume per day.

The profitable futures traders I know are also more or less just riding off the back of the machine volume and participating when machine trading from option flow is moving/pinning markets. They are of course just exacerbating the situation, which is partly why we see this increasingly bifurcated market where robots/options are entirely into control, interspersed with violent price discovery/mini vol events.