Me too, that doesn't make sense to say about 2020 belong to the DEXs and it looks like OP is not even seeing about how much total existed DEX in these days. Some of dexs are having almost zero daily trade volume.
Anytime CEX still dominated the market and that's the fact. We can try to deny that fact when the dex has so many users and Dex started to grow on its quantity in the market too. The growth of dex is still not impressive.