>Other coins are clearly superior in functionality (except maybe the hash rate).

This isn't true, and the opposite is quite true.

Bitcoin is the only coin that seems immune from a 51% attack. Every other coin has a significantly lower threshold needed for people to commit a 51% attack.

Ethereum and other Blockchain coins are not 'superior', they use the same POW solution as Bitcoin. Often, another coin will discover a new way to make blockchain better, and Bitcoin adopts it later. When Etheruem failed to scale, I sold all of my POW alt coins.

The rest of the coins are centralized, which defeats the purpose of blockchain. Entirely useless as cryptocurrency.

I see a future for Bitcoin and Stable coins. I don't see alt coins doing anything Bitcoin cant.