It is limitation of all mobile devices. Dynamic light on them is quite resource hungry. There are several topics on forum about how to fake SINGLE dynamic light on mobiles, and have it at decent framerates. Mobiles now have a bit weaker hardware (when you think about making games) than PCs had around Doom 3 release and it was 2004.
Also do not overdo all that 3d stuff for your game, even top devices seriously overheat when are running more complicated games. And for eg. I would rather play game for 1 hour that does not have stunning visuals, than play such game for max 20minutes due to overheating even if it had best visuals ever.
Now i may pull this last reason right out of my rear part, but i think most mobile games are player while waiting, traveling, during lunch etc. So game that looks great but makes my battery dry in 30min life is not good at all.