It's hand-picked. Even if you meet all the criteria, it's not a certainty that you'll get it. There's no time frame. You can get it in a month or never. Since you can't exactly know, when it's your time, you don't have any choice than to maintain the account in the same good standing until they pick you. And when you're finally promoted, you will need to keep the account within given limits or else you'll get demoted.
I was a TRS at some point, but i pretty much started, when Fiverr started, the expectations were lower back then. If i can remember well, i was promoted fast.