"Hello Mr. Consumer, if you are willing to use a browser with the DRM extension then we are willing to sell you access our video collection for $8/month". Seems like an acceptable deal to me.
The main problem with DRM for me is that it makes content unusable outside of a dictated scope. So 'ownership' is fleeting, ending once you exit the relevant walled garden.
With rented content I don't care that ownership is fleeting. That's pretty much the point.
On the innovation argument — that locking away data obstructs new ways of working with it — shifting DRM from plug-ins to an extension lowers the barrier. The proprietary bit is smaller than it was.
So I support this move.