This is the core question: is this isolation absolutely perfect, or can it be pierced in any way? Something on a severity level like Spectre/Meltdown - people would have laughed you off the stage half a year ago when you told 'em you could read kernel memory from Javascript without exploiting both the browser and the kernel - is IMHO certain to be present in either of the "management" solution, and I'd like to be prepared when the bomb explodes.