Coinbase is the only publicly traded exchange that I know of? Coinbase wasn't public until early '21. So sure, VCs might have piled more money into Coinbase at higher valuations, but all of that VC activity and valuation is an inexact science without a liquid market.
At any rate, off the top of my head, the dot com era had a similar vibe. And several tech firms are down 75+% this year so far (Netflix included).
In which prior downturn were they even listed?
Does it really matter? It's almost assured that private valuations will get written down with a lag (already underway). Favorable public markets are what allowed VCs to foist the turd on the greater fool for a decade.