Because some of those 3 star recruits outperform their ranking and develop, or are late bloomers, and become studs with us. Some of them were missed by recruiting services altogether. If you've evaluated a player and believe they can develop into and SEC caliber player and starter then you take them. If they leave you replace them. Invest in kids early and hope they honor that and stay.
If you haven't noticed the ones we've lost as freshmen and sophomores weren't contributors and went to lower programs.
In your scenario we would've taken the 4* RB Williams a few years ago and told Dylan Sampson to call us after a few years at a small school. Williams did nothing and transferred. Sampson was ahead of him on the first depth chart. If we had done what you suggest, because Sampson wasn't a "blue chip", he probably never would've worn orange.
