Rossi did what he did to become competitive again under very new, and very restrictive tyre supply regs that essentially made Michelin, and their approach, uncompetitive.....if these restrictions weren't put in place, Michelin would have continued to dominate and Rossi or Dani would not have switched. I don't blame Rossi for it as it proved to be hugely successful and the right move (unlike some of his more recent decisions!)
I actually wasn't on board for him dumping Michelin at all, I feel for Michelin as their financial management let them down in the end.....IMO they were far more in-tune with this type Motorcycle racing than Bridgestone ever were, and had they had the resources to continue or at least put a tender app in for the sole supplier rights, then it could have been a far different story......
As we are seeing now, Bridgestone is providing 2-3 choices all that work in a very similar and narrow range.......typical of what they have always done. The sport needs to be opened up to competition once again....only this time the supply restriction needs to be lifted.....there is no doubt that Dorna and the MSMA's cost cutting measures have all only proved to do the opposite.....what harm could be done by letting the teams and riders have the choice of rubber, which is being constantly developed for a motorcycle....not the other and more costly way around.
I am opposed to the control tyre for similar reasons to you and was from the time it was first mooted.I had no objection to rossi going to bridgestone either, one of the few non-rossi fans to have this position, as long as no coercion was involved; I tend to think there probably wasn't and bridgestone were happy to be supplying tyres to rossi.
I don't think bridgestone can be blamed for the current situation though. They didn't want the control tyre either, and michelin didn't tender to provide the control tyre.I think the demise of the sns tyres was with michelin's approval as well, the cost of supplying such tyres being unsustainable, not helped by their overall financial situation and the gfc as you imply.
The blame for michelin's demise can be laid firmly at the door of dorna and rossi, and subsequently pedrosa, and any conspiracy was by them. If you want to argue that dumping michelin, the long-term supplier and rusted -on supporter of motogp was unwise, I agree. It was an example of short termism, not least by rossi.