Yes, the war just started and things are heating up. I would think the next few years will result in a tablet OS distribution that looks like this:
iOS - 35%
Android - 40%
WebOS - 20%
RIM - 5%
Apple - 35%
HP - 20%
RIM - 5%
Samsung - 15%
Moto - 10%
LG - 10%
HTC - 5%
Maybe Microsoft will wedge their way in, maybe the percentages will be shifted around a little. But the growth of the tablet market will stabilize or at least stop growing at the rapid pace that it currently enjoys.
The point I'm making is that the hot market only seems to be lasting 4 to 5 years. 10 years ago, MP3 players was the hot market. 5 years ago, smartphones was the hot market. This year, it's tablets. 5 years from now ... who knows, but it won't be tablets.
Don't apply the phone dynamic to Tablets. Android is not likely to take a lead in tablet market share for a long time if forever.
Every single time a customer goes to buy a tablet they will have the choice to buy an iPad. The only way that changes is if the wireless companies are able to give away cheap android tablets with data plan contracts. Otherwise, it is going to be very difficult for the commodity android market to overtake Apple.
Every store they go to, an iPad will be there next to it, and since Apple took such an aggressive price stance from the beginning, it is going to be hard for anyone to take that position away from them, especially a mish mash of opposing companies relying on a free OS by another party.