I think as soon as there is a comm protocol that is worth calling a winner (works well, widely supported), it will quickly become the case that LED bulbs and fixtures will come with it built in. A while after that, whole home lighting control is a $100 feature that you expect in every house (or less for smaller places), not a $500 or $1000 feature that doesn't work very well in houses where the owner really pursued it.
I don't expect there will ever be such protocol though, there is too much competition already and everyone wants to be the "platform", because no-one actually has any idea of what gadgets would be useful. Even if we just look at the low level, there already is a war between grid powered vs battery powered, which then influences the war between BTLE, WIFI and ZigBee. There are inherently very different architectures, I don't see a change for convergence. But then probably when everything has been already done Apple will invent THE Apple Home which will be (as always) the first of it's kind :)
Could be. There is some chance that hubs like Wink (which supports ~6 protocols) will encourage manufacturers to choose the ones that work well. Then someone just needs to make a similar hub that isn't architecturally tied to the internet.
