That's an extremely interesting point (to me), because I can't quickly/easily provide the answer. It's been my experience that LBD maxing is more addictive than experience grinding (even when that experience is earning points which are "spent" on skills which would seem on the surface ultimately the same as LBD).
If I consider my experience with the Bethesda Elder Scrolls (Morrowwind, Oblivion, Skyrim) I think of how LBD all but ruined the RPG leveling feel. The convoluted way they tied skills with stats was counter-intuitive once you passed the mid-point of leveling. Don't get me wrong, it's great at first, but leads to some LEGENDARY-long spam skilling sessions that have little to do with gameplay.
Another LBD game is Wasteland 2. I remember starting and loving that game, only to restart a couple more times and quit. It's my own fault of course...my mental need to max things and the MANY skill checks against your skills dragged you far away from the gameplay and heaven-forbid, story of the game.
It's got to be a purely psychological thing, but the generic "XPs" and levels we gain in most games still gate our abilities, but since in 7D2D for example I can gain XP in many ways and then apply it to certain skills/stats, it's more generic and thus (I think) I am less driven and focused about any given "merit badge". I find myself breaking rock until I'm sick of it, then I kill zombies until that tires me then maybe I go do a quest. Previously I'd be making bandages and wouldn't stop until I finally got that point of Science after an hour.
Given the choice of making bandages, or choosing a variety of other activities which are much more associated with actual gameplay, I choose the flexible generic option.
I WILL say that I'm open to a hybrid system, but it would need to discourage pure LBD play. Diminishing returns on LBD in a given day seems the best option AND that MUST be for ALL LBD...otherwise after I'm done spam-crafting stone axes, I'll just move on to jumping a lot and then making bandages; cycling through all the skills until another day has past. I.e. once you've reached the maximum that you can gain from LBD in a day from any and all skills combined, you're done.
-Morloc