All the gains with btc were made already if we are looking for 4 years from now is only 2-3x .
ETH I could see 5X in the next 4 years it has lower marketcap and better roi.
Well, I have to see what is your basis then.
Honestly, what you have said is just pure speculation. Will if you can see the journey of Bitcoin and its price improvement, you can really see that it was growing which I believe that you are wrong with your presumptions.
Don't fall into the wrong beliefs, Bitcoin is growing and really sustainable. May the altcoins are not but those leading coins are going to stay and will grow together with Bitcoin.