What do you think?
No one knows on what bitcoin isn't still being replaced yet in spite on being outclassed by most updated or good featured altcoins in the market currently.
But we can already presume that Bitcoin is king of crypto that's why its being mainly supported by the masses in spite of its scability issues.
And also I think because there are some widely spread supporters of bitcoin. Altcoin also depends on the price of bitcoin and all wallet was supported bitcoin that's why you can firstly known bitcoin before altcoin.