You can argue that the spread turns some off, but the truth is more and more teams are running a version of the spread and the NFL is now starting to incorporate various elements.
I'd definitely argue the spread. Your counter points are absolutely correct, and will change OL recruiting going into the future, but the perception that you're more likely to be a high draft pick as an OL in a pro-style system is definitely out there. There's a reason why even down UM teams have won battles for OL recruits with OSU in the last few cycles. Especially early on in Hoke's regime when he was pushing the "we're going to commit fully to playing a pro-style offense" line; which they have to some degree, just hasn't been effective. I think we'll see the perception start to change though, and recruiting with it.
Also, just my two cents, but the way recruiting sites evaluate OL recruits (in terms of who is top tier and who isn't) is conducive to pro-style teams as well. A lot of the heavy grapplers that excell in pro-style systems, and are ranked very highly by recruiting sites, don't quite fit what you're looking for out of an OL in a spread system (which is built around pace, conditioning, athleticism, etc). I could be wrong on that, but it's my perception based on following recruiting the last few years.