Here you can say every month new altcoins came and some of gone but here the bitcoin is in stable from the 2008 which is really a quality of king .
So here chances of replacing the bitcoin by another altcoin is only 1% or even less .
There was an attempt for the development but its just something that might just worsen the situation, there is a serious problem with the current version and those miners are pretty much wanting more of a decentralized system. They feel like they are being ignored which I think they are really. A little increase of blocksize I think won't hurt but instead they push the blockstream.
The fork can easily by FUD by individual who have some motives so we now know things are different these days than those before where users are only aiming to see bitcoin to be used by individuals. Today, the users are often aiming for profit.
Sooner it will be replaced.