The way I see it, bitcoin was first so it has some predominance over the market, people like things they feel comfortable with, the OG of crypto. I don't think it will hold it's place for too much longer though just because there are quite a few altcoins which have greatly improved the model.

I think that if people can get enough nodes setup on a crypto like Raiblocks, people will eventually go towards those that have no fees and very fast transactions.