This article is a little outdated, but it's one of the better breakdowns I've seen. I'd imagine the numbers hold about true today, but maybe not.
It's a popular time of year for people to throw around stats of three-star recruits dominating the NFL Draft. But if you look at the percentages that's not really the case ...
247sports.com
Basically, yeah, you have lot more 3* and lower drafted because there are a heck of a lot more of them. For the 2018 draft, though, a former 5* had a 57.6% chance of getting drafted while a 3* had a 6.9% chance. Your chance of getting drafted decreases with star rating.
Of course, the article was written by 247 in defense of recruiting rankings, but the numbers are the numbers.