I do not think a President Trump would make the same mistake. I believe he will bring a lot of talent into the Administration and likely not one but several of them will emerge as serious future presidential candidates. People who we are not even talking about today as being major players.
So in Trump's case, he may decide to go with a seasoned vet for now over some young upstart. I believe he's always thinking well ahead.
I agree that Bush not only had no heir apparent but didn’t bother to try and find one either. Pence is both young and seasoned. At 57 he has a long future ahead of him. And should the worst happen, he would make a good president.