The belief (consensus) of a group of the same kind can only be one (otherwise they are not the same), but there can be countless ways of application! BTC is obviously the former, while ETH and its successors are bound to be the latter.

In terms of the evolution of the industry:

BTC is a digital currency, and it is only a currency; ETH is a financial application and it is only a financial application; DOT may have the potential to interconnect everything, but the slot threshold is too high, which is not conducive to popularization.