From 1:
"Most of them arent ditching their computers altogether, but an increasing number of iPad users are spending more time on the tablet and less time on a computer." - That is the issue. Even if I have an iPad, I still need to have a computer to do some things. The iPad cannot do it all. With a Surface, I can ditch the pc/tablet pairing and just go with a tablet.

From 2:
"While that full desktop environment on a tablet could be the killer feature for power users, it could also be the crutch that kills the Windows 8 tablet experience for everyone else." - Not getting your point. If a user goes with Pro, he/she can continue using the software and things they use today. For those this looks like a UL/UB killer. In truth tbd.
But RT. This would be investing in a new ecosystem that looks like the Windows (mostly) of old. It will require a completely new investment on par with moving from iOS to Android or vice versa.

From 3:
"Are Apple, Amazon, and Google wrong?" - yes and no. iOS is ontended to be used NOT as a pc OS but more as a "time waster" device; aka a device that you consume from, not produce with. Lots of people have tried to produce. Android is the right way but really suffers from two things: being open source and allowing the OEMs (who cannot escape the budget pc label) to play chaotic with what could be done. Amazon is another more focused equivalent of iOS. Google with the NEXUS has the right idea but has not implemented it well. Surface could give users the best of all with RT if they can convince users to reinvest in a new ecosystem. That will be the pivotal aspect.

It looks to me like MS is on the right path provided they can pull it off.
Unfortunately, historically that has not been in the realm of their skills.