By looking on coingecko, you can notice a volume declining over the years and I might identified the issue, that could be seen as an iceberg.
Visible level : Spot/Perp/DEX prices
Deep level (not tracked) : crypto-swap exchange, localmonero or atomicswaps
Theres a looot of volume not tracked in the deep level, since a monero user is most likely using these ways (just look the last bad new it was a "nokyc" swap)
Based on the current liquidity on samourai swaps and BasicSwapDex, I doubt there is THAT much volume going unnoticed but there is definitely some. I'm very interested in what SeraiDEX will reveal about Monero.
I mean, all theses swaps going on "non-custodial" exchanges, their volume are not tracked. they probably represents a lot of transactions involved in circular economies. 600k tx in February while theres less volume isnt make sense
BasicSwap DEX Desperately needs an appimage release and an option to connect to remote nodes. That way anyone on any linux can just use it. If they do not do this they will have 10-15 users.