There is only one bitcoin. If you want to invest in cryptocurrencies you would be smart to look at the utility and applications of the coin you are involved with.
If people can find better alternate coin where they think that investing in that crypto will yield them better profits than they can invest in that as well because if research done proper and future holds good then one can stay invested in such coins .
Well, that's correct, I believe major investors are not only investing in bitcoin but they also invest in altcoins.
The reason is because they also believe that altcoins has a big future, the crypto market will be getting bigger and bigger as more altcoins
will be created and even if bitcoin will remain the king or the most dominant coin in the market, altcoins still has plenty of room to grow.
I think mayor investors invest only in altcoins they really believe in with regard to the future - altcoins which are different from BTC, altcoins that have other features or possibilities. Altcoins that are innovative.
Altcoins that are that different from Bitcoin might have a future as long as they're innovative. Altcoins which are similair as BTC might have future if they have a solid history and community - which is the reason I think many new BTC-"copies" are doomed to fail.
Overall, for me it's clear that I should stay true to Bitcoin for a huge part of my total worth. A small percentage of my wallets will be in altcoins, most of it is in BTC and will always be.