Is it pointless to buy ether or any other crypto currency now?

Let's say ether goes to 7000$. Even though that's an increses in more than 3000$, that's just multiply by two. So if you had invested 10$, you now have 20$. That's the same as ether going from 1$ to 2$. Ether has increses it's value by x3000, that won't possibly happen again. Isn't the best part over? What am I missing?