Who takes the time to read manuals anymore nowadays? Who pays meticulous attention to the endless in-game tutorials intricately explaining the ways of the leveling, combat, skills, magic, etc etc... systems?
We just want to hop in and have fun, and the worst thing to ruin that is, worrying about having potentially missed some critical detail in a console RPG's menu, that later on hinders our progression and overall enjoyment of the product.
Enchanted Arms which I currently play, constantly has to pause in order to let the various characters assist the hero and explain the particularities of the possible actions in the environment, and the various possibilities of the menu system.
Sure, deep menu tactics are meant to give replay value to the titles, but there's a reason why two of the original games in this now crowded genre, Dragon Quest and Final Fantasy, are still the most popular and notorious ones in the world. The competition has to differentiate itself from these two franchises with particular battle styles, upgrades, weapons... but in the end it's just cumbersome.
This generation Dragon Quest VIII and Final Fantasy X were the two most successful RPGs, and they managed to keep their simplicity too. These are the sole two ones I could see myself playing again... and then again probably not, games just get too complicated nowadays, and now we have a truckload of RPGs everywhere available for cheap, who'll really replay the old ones in his collection, when it's much more preferable to experiment a new adventure after another? And the biggest hurdle to that is what I described above.