Bitcoin is essentially just a protocol, if you look at it from a purely technical point of view it reminds me a lot of IPv4. People have been predicting it's eventual demise for over 20 years and the way things are going, will be doing so for another 20. Incremental improvements to an established protocol are very often more than enough to keep better alternatives from gaining the necessary critical mass to take over. The tech sector is littered with similar examples. There are notable exceptions but most altcoins are themselves nothing more than incremental improvements over bitcoin.