Well a lot of reasons. One is 2000, 2001, 2002, and 2003 drafts inflate these numbers greatly, and we weren't in the ACC then.
35 total draft picks
19 first round picks
We haven't had good enough QB play, we haven't had good enough WR's, and we haven't had enough quality DL for a good majority of those years. Overall though the administration neglected the football program from a resources standpoint for 20 plus years, and hired too many Head Coaches that weren't quality.
Our Head Coach salaries were typically middle of the pack in the ACC, and our facilities before NIL were severely below standard when that type of stuff was important. It led to uneven recruiting and talent acquisition. We didn't have a first round DL from Vince Wilfork all the way to Greg Rousseau.
We went from Andre Johnson to Phillip Dorsett in WR's drafted first round, and haven't had one in almost a decade.
We went from Dorsey to Kayaa in QB's drafted 7th round to 6th round.