My opinion is that in time Bitcoin market share will keep reducing, as many other coins and tokens and platforms will keep surging.
In the long term, the blockchain technology is very disruptive. Bitcoin will more likely compete with Gold, Ethereum will provide a backbone for many uses.
So I am not really sure a collapse is incoming, it depends if a real bubble will quickly form.
I believe that bitcoin dominance is currently massive undervalued.
It's almost like the gold:silver ratio right now, just like silver is massive undervalued compared to gold, bitcoin is undervalued compared to the rest of the crypto market. A lot of people are flooding to new projects with absolutely no understanding of what they are practically going to address. And most of these newer projects are going to be replaced with even newer ones in the future, while bitcoin remains the only real long term asset in crypto.
BTC isn't going anywhere in the long run. In fact, it'll be the best long term crypto to hold, and history has demonstrated that. The fact that bitcoin is the most widely adopted, practically used, and simply the first crypto to exist, means that it's intrinsically more valuable, and trusted by many more people. I think bitcoin dominance in the long run should probably belong at least in the 60-80% region, which right now, isn't even 40% which is ridiculous.