It's a good point, and I've thought about that one too and the only thing I know for certain out of all of this is that people won't pay 500 bucks for a tablet computer unless it has an Apple logo on the front. The new Amazon 7" tab for example is rumoured to come in around 250, so it might sell quite well.
Speaking as just one webOS end user, if someone brings out a Touchpad 2 or equivalent in 18 months time, I'd happily pay 300 for it.