Besides the usual pathos of all the folks losing their jobs, there's a whole subsection of the internet that would disappear / severely shrink.

You might argue that it probably wouldn't be a huge loss but that would be your perspective there.

Nevermind the fact that the ad serving market, once you remove FB/Google/AMZN, is actually quite broad and diverse, especially in the display/programmatic world.

This being said, Chrome recent announcement wrt privacy & 3rd party cookies might be the final blow for a lot of indies. Not that I disagree with you and I believe a culling and a new approach is required, one that purposely avoid the SV giants and centralisation of data.