What people don't understand is that you can not compare Bitcoin with those projects. Even if the price of Bitcoin is going up, there is a very high possibility that the price might not go up. This is all part of the reason people are always advised to invest in Bitcoin because it is the one driving the market. When you invest in Bitcoin, there is a higher chance of winning. It is better to go for the one that is winning.
There are other coins that aren't a bad idea, but at some point, you can strategize your own way of investing so you can do both bitcoin and altcoin, so we just need to know how to make useful of the information we have.
Depends on the strategy of the investor. If he has already invested in Bitcoin and he sees himself looking forward to own some altcoins, that's on him. No one can stop him from that decision.
But it's true that people are investing on Bitcoin because we know that it's going to get up no matter what happens to the situation of the global economy.
And then, those that likes to diversify are likely done with their accumulation of Bitcoin. Well for some, it's already enough but it doesn't stop there, right?