If you count the number of coins and tokens that are dead now, there are thousands of them.
That is not just the problem, the problem is that many coins are just not increasing. They will increase, later fall and not get to all time high again. They are not assets of value but assets of gambling.
Bitcoin is very different because it is an asset if value.
The real problem is, these coins aren’t made for success, aren’t made for real utility cases and aren’t made to achieve the same potentials with bitcoin. Simply put, bitcoin is the only OG, while these altcoins are the pirated ones. Those who chose to prioritize altcoins over bitcoin, they are most likely gambling and just depend on luck to gain, while those who stick with bitcoin, they are the true investors with bitcoin.
While both bitcoin and altcoins are considered assets, but the real question is, as to when these kind of assets will remain valuable in the long run. And I think bitcoin has proven it a lot of times.