That's the mistake of many Proof of Work altcoins: they use their own hash functions, or mine their own chain of the heaviest work, instead of being connected to Bitcoin by Merged Mining. The same with Proof of Stake: by creating new altcoins, the situation is not better, it is actually worse. Users don't need new coins, they need new features on existing coins.

There is Merged Mining, there is Merged Signing, there are ways to make new features, without creating coins out of thin air. I still don't get it, why altcoins do that, when there is no need, and when trading and speculation can destroy them, even if their idea will be genius, just because developers force users to choose between coin A with feature A, and coin B with feature B, they enforce choosing for no reason, why they can't just get feature B on coin A?