The don't need to hold proportionally less. It's a red herring.

The focus rather should be on health/nutrition outcomes, education outcomes, physical safety, quality of housing.

And this question is... is it getting better?

Factfulness says yes. Slowly, but surely, yes.

It's not about money. In fact, money is the completely wrong way to think about it. The vast majority of the wealth of the wealthy is in the form of ownership of businesses that efficiently produce goods and services for others (not for themsevles - this is important). If you take these businesses away from them and give them to the poor (who are likely not going to be that great at managing said businesses), the effect would be to make the poor poorer, as well as humanity as a whole.

Most of their wealth isn't money, it's property, land and businesses.