Last year, I did a simplistic analysis of the 247 sports all-time rated recruits and I found zero difference in attrition rates of the 3 and 4 star recruits. I decided that guys were contributors based on stats, snaps, starts, tackles, yards, etc and I found that roughly forty percent of the 3 and 4 star recruits did not contribute. It might be true that four stars are more likely to be all-conference/all-american but I don't want to spend all day doing the analysis. You can look at the last few classes and see that a lot of four star guys did not live up to their ranking and I've been following recruiting for 25+ years. I linked the 247 sports all-time recruit list below.

A recruit's ranking goes up when they get more offers from big-name schools. FSU had top ten recruiting classes from '14 - '17 and they started to stink in 2017. The analysis in the article below shows that over 50% of their recruits didn't pan out and that's not unusual. Clemson has had great recruiting over the past four years but they now stink.

https://chopchat.com/2018/11/27/fsu-football-noles-past-recruiting-rankings-fools-gold/