Bitcoin won't die. What would happen is litecoin would be one of the closest competitors of bitcoin on the market someday just like ethereum. But I agree that litecoin is rising faster than bitcoin and I hope it would not stop.
I don't think that bitcoin will die in the medium term, but rather that the crypto market will not be having a single, clear leader, and "a lot of shit coins" ; it seems to me that such a market configuration is simply not possible in the long run, because *it would be too easy*. If there is one single dominant crypto, then it is pretty obvious that that's the crypto one needs to "invest" in, will grab all the greater fools, and will be solid and growing for years. Such is not possible. If a lot of smart money KNOWS that a single asset is going to rise at important rates for years, and most normal people know that too, they are not going to wait to be the last greater fools, but buy directly. Hell, if you knew with certainty that bitcoin was going to rise 50% per year on average for the 20 years to come, would you "spread your acquisitions" over 20 years, or go all-in right now ?
But if all smart money goes in "right now" we would have a HUGE price rise in short time, and then, a stagnation and/or a crashing of the bubble, because once it is high up there, there's no much hope for big gains any more.
So a clear, single, obvious, leading crypto that grows for years and years at astounding rates is simply not possible: it would be too easy to see, and everyone would have gotten in near the start. However, an opaque market where things sometimes rise, to fall down again, and transit their market cap to others, in a rather unpredictable way, is a market that could, indeed, rise for years, without a single, clearly defined, absolute leader for all these years. During certain years, a crypto may get the illusion that it is the leader, but it cannot be with certainty for a long time, with a lot of smart money around.
Because the more it grows, the less head room it has, while other coins are cheaper and the ceiling is further away, so there's more chance for growth.
Now, that's just my theory. Maybe smart money is more stupid than I think and just follows its dick. And it is also under the hypothesis that crypto is a speculative token market, and not something that is really driven by actual usage.