Compulsive draws three of the average power level of your cards, Revival recurs the best possible card from the graveyard for that situation, so it's not like Compulsive is drawing three times the card value. Compulsive can just as easily draw three lands (close to zero value in some situations) as it can set one up for a banger turn [cast + 1]. You aren't generally casting Revival on curve, which is where the comparison to Research, which is commonly cast on curve, can break down some. You are probably in dire straights if you are casting any regrowth on curve, and you probably aren't playing in most of our environments if that's happening, because you shouldn't be in dire straights by turn 3 in general. That implies a turn 4 format, which is modern speed. Obviously it can't recur from an empty GY, but that's true of every graveyard recursion ever.
And the three mana part isn't really what sells revival anyways. It's the flexibility to recur a card from the grave by using another card that's also in the grave, giving the potential to basically come back from nothing. The same basic reason that
Rites can sell itself, even though a 5 mana front side is pretty mediocre.