I don't know if bubble is the right word but BTC will remain the strongest for a long time yet I reckon. However, does this mean forever? Absolutely not. Crypto is still SO new, who knows what will happen in 10 years time.

In terms of right now, this past month though - I reckon we're in a bubble and the BTC crash will happen soon.
(At least I hope so for the sake of my poor alts!)