The odds of a high ranked QB being a bust are actually lower than the odds of a developmental kid playing above his means in 4 years...
A lot of high ranked QB’s do end up as busts, but the developmental QB’s really only develop in systems that are actually conducive to their development, primarily high volume passing teams.
Banking on a developmental QB is just as risky as banking on a high ranked QB, both scenarios require for the QB to thrive in whichever Offense they play in; the odds increase as the offenses vary & you’re less likely to develop a lower ranked QB at places like Wisconsin, Iowa, Boston College, Minnesota, San Diego ST etc, vs say programs like Purdue, NC ST, Wake Forest, Oklahoma, UNC, Louisville etc.. Meaning if your formula is to take a lower ranked QB & turn him into a legit starter by his Red Soph/Junior season it has to be a certain kind of system.
OH ST, Clemson & Bama are the model of how to consistently recruit & sign 5-star QB’s & get them to produce for your program. They may not turn out in the NFL, but as long as they help your program win in college, the NFL aspect of it is really beside the point.