I think it's just that Spurrier and company are simply getting outworked.
Spurrier is a better coach than DS, no doubt about it and it's not even close. BUT Spurrier has never been a great recruiter... at Florida that wasn't a big deal. It's more important at USC. I think that USC has had the great fortune the last 5 or 6 years that some REALLY elite talent has come out of SC AND that USC got nearly all those players. Now the talent pool in the state has trended down a bit and perhaps some of the new assistants under Spurrier aren't as good at recruiting as some of the guys they replaced.
Dabo and company aren't afraid of hard work. They are constantly on the road visiting commits, recruits, and prospects with one purpose in mind. Get them and their parents on campus. There is a whole system in place to sell Clemson and it's a well oiled machine. Probably the best thing about it is the number of former players that come back to campus to "visit" while these recruits and their families are there. It's a huge deal to parents and potential players when they see former players (NFL'rs and folks who just got their degrees)... especially Mamas. Dabo knows how to play that game well.
Granted, I'm on the outside looking in at the USC program, but I don't see SS working as hard for the commits as Dabo does.