I'm surprised that you don't put decentralization at the heart of cryptocurrency. Yes, cryptocurrency has crypto-based encryption at its core, but the original idea of cryptocurrency was that you don't need to trust your money to a third party. And the centralized system is in fact a third party. So you're wrong to say that cryptocurrency shouldn't have decentralization.
If decentralization is the heart of cryptocurrency, the coins listed on CMC or Coingecko might be around 10-50, not 2K. Because 95% coins are centralized and it shouldn't be included as a cryptocurrency, then why it's included?
I don't see any other trusted decentralized coins except Bitcoin, Monero, Litecoin and DAI. There's a decentralized coins, but the marketcap is small and has higher chance to suffer 51% attack.
I'm not saying centralized coins is good, but I just want to be fair.