Mark my words: Windows will become a Linux distro that includes a good compatibility layer that people will take advantage of in other distros, and this will mark the year of the GNU + Linux desktop
It can happen if Microsoft decides not to spend money on making a new kernel because they will need one eventually. But a compatibility layer? Why would they not make it exclusive to Windows?
I don't think it's guaranteed that Linux will be a viable kernel in a future where NT's forced to be abandoned unless it's simply because Microsoft refuses to maintain it. Linux is older than NT, so if age alone killed kernels, it'd die first. I think it's a pretty safe bet that Linux can be kept viable for a long time, so if Microsoft wanted, they could keep NT viable for a long time.
Edge is based on Chromium which is arguably one of the more secure pieces of software in existence. If it wasn't it would be exploited immediately.
Meanwhile Dillo is some hobby project that only has 14 contributors. It lacks the sandboxing provided by bigger browsers and has very few users let alone security testers.