…and SushiSwap is just a copy of UniSwap code (Cut and Paste Style). PancakeSwap is Binance clone of UniSwap, etc… So, these aren’t really development teams. These are usually a few people that are trying to get business going on already developed platforms. These aren’t blockchains, they are basically programs running on blockchain. When you asked " Why do blockchain dev teams remain anonymous?" , I assumed you meant actual blockchains, not Dapps or software.
Dapp or software teams may be anonymous because they live in a country that outlawed crypto, or they don’t want to pay to incorporate their business, or they want to avoid taxes, or they are not sure if it’s gonna work so they don’t wont to destroy their careers. Either way, they usually don’t develop anything. They try to repurpose what’s already developed, so they don’t commit much to the project. They can easily walk away if it doesn’t work out and the reputation will not follow them into next business they try to start. (or it could be a scam).