I agree with you regarding market loyalty for WEBOS but I'd argue there isn't any real market loyalty for the other OS's either. Android is a commodity OS on many different devices and the real loyalty with Apple products is to the overall design concept, not to the OS.
Users don't care at all about the OS on consumer devices, they just want them to work.
In an emerging consumer device (such as tablets or smartphones) people care about the OS as some of the OS's work better than others and are better supported with new features/functions (apps).
Once you reach full consumer device status it doesn't matter what the device is - it just works and does what you need - TV, Hi-Fi etc.
I think this was in many ways the genius of Apple with the IPhone and the IPad, they took complex devices and made them things that just worked out of the box, without needing to really read any instructions.
I haven't bothered flashing my WEBOS touchpad with Android because out of the box it does what it needs to for me - it reads ebooks with Acrobat Reader and comics with Comicshelf HD, it was easy to get the apps to make it do these things without reading any manuals.
The system tells me when it wants to update itself (same as with my TV), there are some more techie things I can do with it if I really want to but thats a bit like trying to hack my TV in that I might put Android on the Touchpad at some point because it will be fun to do but I don't NEED to do it.
In terms of opportunity Apple win by being the most consumer focussed, Android wins by being almost everywhere thats not an Apple. I think WEBOS could potentially get a lot of Androids space.