Agreed. To do this correctly would take long term planning on the scale of decades most likely; growing the faculty from within and providing the necesarry resources to develop them. But it is possible and the elite universities should be moving this way.

For Harvard and the rest of the Ivy League, "growing the faculty from within" really means "actually granting non-world famous people tenue." The Ivys are notorious for not granting tenure to people who come up through the ranks.

You can’t just hire more top talent. “Elite” is “best”, not “more”.

The academic job market is so tight in most fields that random universities in the middle of nowhere get hundreds of applicants for a single tenure-track job. If you go back 100 years ago you would find that Harvard was a lot less selective (there were far fewer academics), but it was still elite.

Overall, society isn't putting enough money into research. Elite universities hiring more faculty would be a great thing, in my estimation.

You absolutely can hire more top talent.