This is a very interesting question, because I myself have wondered that on multiple occasions. In fact, when bitcoin reached the $10K line, I set out to start accumulating more ethereum than bitcoins, assuming that bitcoin's growth potential would already be quite limited and a big correction could be near.

However I see that time passes and the upward trend of bitcoin seems to increase every day instead of decreasing, so now I'm still buying bitcoins, almost in the same proportion as I invest in ethereum.