According to Vitalik Buterin, there are three main features: scalability, decentralisation and security, and all projects can have only two of them. And for sure, we have a scalable Binance Smart chain, Polygon, Solana but all of them are centralised.
But maybe Ethereum 2.0. will do something with it. As it promises to become more scalable, on the other hand a big part of validators are centralised exchanges like Kraken, so can we talk about decentralisation then?
Exactly. There needs to be a balance between decentralization and scalability for a cryptocurrency project to stand the test of time. Otherwise, it'll become a centralized "banking system" subject to manipulation, fraud, and corruption. Cryptocurrencies like XRP and Stellar are highly scalable "blockchains" but they're utterly centralized (especially XRP). Most people don't care about decentralization these days, so they'll use these kind of cryptocurrencies even if they experience huge losses in the long run. Convenience/ease-of-use goes on top of everything else these days. As long as people don't care about decentralization, centralized projects will only become bigger over time.
I believe "unlimited scalability" is possible considering how Blockchain tech is capable of processing thousands of TPS. But a cryptocurrency with such model will have to sacrifice decentralization/security/reliability in exchange for high performance & low costs. I'm fine with Bitcoin and Ethereum having their limitations as long as they remain decentralized and censorship-resistant. Just my opinion