If the price of the Altcoin goes up, then the Bitcoin value will go up. The reason is that when the price of Bitcoin goes up, the price of Altcoin goes up as well.
If people start buying Altcoin more than today, the price of Bitcoin will go up as well.
If the price of Bitcoin goes up by 2021, it will be a record.
Am I right?
Firstly, there is no such thing anyway. If 5 are invested in altcoins, at least 10 are invested in Bitcoin. Secondly, let us assume that the situation has developed as you think, but this time the result will not be so. Because trader sells Bitcoin for getting altcoin. In this case, Bitcoin does not increase, on the contrary, its price decreases.