It seems to me from my ignorance as a newbie. It seems to me that this is mostly due to the large amount of cryptomonniques that exist today. It's as if we used to have a pipe with a single faucet, there would be a lot of flow through that single faucet, now there are many faucets and many pipes. It is saturated and lowers interest, but will always have some growth.
True spread out across all is very possible not really hard to pull those numbers however for all major crypto currencies all transactions are down back to 2016 levels.