Getting rid of hereditary nobility has worked out pretty well for the USA.

Has it? By what metric are you using for that? Two Bush presidencies off the power of the senior patriarch. Current president comes from family wealth. Most of the oligarchs come from family wealth. It's not until the recent tech billionaires that became first generation oligarchs.

We've got work to do, but it could be worse. Point is that the problems of the USSR weren't caused by getting rid of the hereditary peerage.

Well, for all USSRs issues, getting rid of their nobility was one of the best things they did.

It's what fills the vacuum that matters, just as POTUS is finding out in Iran. If you don't have a plan for after creating the vacuum, you're probably not going to be happy with how it is filled