For me, Bitcoin is a phenomenon that is very difficult to explain. Of course, it can initially be assumed that Bitcoin was conceived as a means of payment, but they will never use Bitcoin for this, because even the transaction speed is not too favorable for this and there are quite a few other problems on the way to implementing these plans. In my opinion, there are many cryptocurrencies that in terms of characteristics can be better than Bitcoin, such as Ethereum, but nevertheless, Bitcoin still holds a leading position, primarily at the expense of investors.
It has become evident than Bitcoin will always be the leading cryptocurrency of the world because of its unparalleled development and innovation. People tend to trust it more than any other altcoin because of this. Of course, the value or price is largely determined by the investors themselves. Considering that Bitcoin is the first cryptocurrency ever created with an innovative technology (Blockchain) that promises to change our economy for the better, it's no wonder why it has so many followers behind.
Personally, I wouldn't mind if Bitcoin gets a market dominance of 90% while other altcoins sink both in price and user adoption. It would greatly show us how strong Bitcoin is relative to other "copies" with no future or real uses cases at all. Despite this, there are only a select few altcoins like Ethereum and Cardano which are quite unique among the rest of the pack. As Bitcoin continues to rise in price and user adoption, we'll get to see other altcoins abandoned by the people in favor of the original cryptocurrency. Still though, crypto behaves strangely (unlike the real stock market) where no one can predict what the outcomes will be within the future.
While there's no doubt that Bitcoin transaction speeds are low, and fees are high, there's already a solution in the works that's bound to make Bitcoin bigger, better, and stronger than ever. This solution called "The Lightning Network", could take Bitcoin towards new heights in market dominance if successful. Perhaps, that's why many people say that most altcoins will be rendered obsolete or useless in the future.
Nonetheless, I believe that we're heading back to the events of 2013 where Bitcoin's market dominance was around 95%. As soon as the next bull market takes effect, Bitcoin will be the cryptocurrency with the most gains making this a reality. In the end, it's up to us as early adopters of the cryptocurrency to hodl for the long term no matter what. Just my thoughts