If it is a perception issue they're worried about, why allow it on the upgrade and retail versions?
The difference is that the upgrade and retail versions are intended to be installed on existing (i.e. old) systems by the current owners of the hardware. System builder licenses are intended (but not required) to be installed and then sold to a third party.
For existing owners of less-than-ideal hardware, the reduced touch feature set is not great, but not nearly as bad as what drfish experienced. MS wants to avoid making end users mad, so for user-performed installations, they chose the least offensive thing they could do.
For system builders selling to end users, MS would
much rather upset the seller than the customer, so they make sure that down-rev hardware
can't be sold as touch enabled, unless the builder/seller is willing to pay extra for a retail license (which would likely more than overshadow any extra profit made from cheaper hardware).
The flaw in this, of course, is that sometimes system builders
are the end users, and they get screwed in this situation. The solution would have been to properly publicize this issue ahead of time to reviewers, who would in turn warn likely users of system builder licensing, who could opt for the upgrade license to avoid the problem.
Of course, Microsoft didn't do the truly smart thing because, well, they're Microsoft and this is the kind of stupid s**t they do. It's just that they're being partly "clever", and partly stupid in a non-obvious way that makes it look like they're just being evil.
The more I think about it, the more it seems that MS has taken stupid to a whole new level that most of us can never hope to attain.
