Sorry, I am not sure Bitcoin can be a niche currency. It needs to be big enough to survive.
If most people prefer to use other crypto instead then Bitcoin may fall into a death spiral:
...lower the demand for bitcoins -> lower the price of bitcoin AND lower amount of bitcoin transactions -> less profitable the mining -> less secure the network -> lower the demand for bitcoins....
If most people prefer to use other crypto instead then Bitcoin may fall into a death spiral:
...lower the demand for bitcoins -> lower the price of bitcoin AND lower amount of bitcoin transactions -> less profitable the mining -> less secure the network -> lower the demand for bitcoins....