RE: What does a hybrid really do that a high end single cam doesn't ?
Here are some information that is stated from various companies on their cams.
Hybrids have straighter nock travel thank solo cams - True & False so neither is the better option it all depends on the cam in question. Some cams such as the Cam 1/2 by Hoyt & the Straightline Max Cam by Mathews have very level nock travel. Is one better than the other? Not really. People have shot bows with very poor nock travel very well so in general repeatability of the shot sequence may be more important in the long run.
Single Cams never go out of sync - another True & False statement. Technically they never go out of tune but they can go out of time when the cables stretch. The hybrid helps this by using a shorter cable length BUT a single cam like the model Pearson made 3 years ago & the one Hoyt made before the hybrid cam will do a similar job. The idler on those systems terminated the string in the idler which gave shorter strings & where less likely to stretch. I think this is a moot point with any cam system anymore, good strings by Winners Choice, Stone Mountain, etc. will eliminate this problem anyway.
Dual cams and Hybrids are faster - True & False again - it all depends on the bow & how it is designed. Hoyts IBO speeds are right in line with the speeds they had with single cams, mathews speeds on the black max are fatser than some dual cams. This another point that is rather silly in my perpective. a bunch of marketing BS on all sides of the fence. You see speeds for all 3 styles anywhere between 290-330fps so I don't see compairing speed traights as an honest answer either.
Which cam is honestly better? The one you shoot better is the only true answer!