Siloing is fine for players and GM's who are looking to play a combat-centric game. 4E is a great example of that type of system where siloing works well.
Those who are looking for more from their RPG will probably want to find a system that is designed to support and enhance more than combat. There are plenty of games on the market (both new and old) that can work for this type of gamer.
What?
This makes no sense.
If a game is focused exclusively on combat (or social encounters, or exploration, or any other single area of play), then siloing is a waste of time. Siloing is designed to support different types of activities, by ensuring that all PCs can participate at a minimum level; the fighter always has some noncombat skills, the bard always has some combat powers.