Formally verified bootloaders and Secure Boot will make this all but impossible without hardware mods that do voltage glitching. It took 8 years for the checkm8 and usbliter8 exploits to be found, and I think that especially Apple has invested so much money, time and resources into securing their boot chain that the "best" thing we can hope for is a tethered jailbreak allowing a boot into another kernel.
If I had to venture a guess it would be that this is the last stand for hackers that are able to root all kinds of older devices, but companies like Apple will shell out the money to prevent this for their next-gen devices.
It's likely that low-cost device makers will not do that, so maybe rooting will still persist for cheap stuff.
But "Open Source" is a description of the licensing terms, and it ain't gonna be that. Apple will sue hosters into oblivion. It will only be available on pirate sites.
We already have nearly a dozen of Adobe and Autodesk knock off apps.
A clone of autodesk may be open source however.
It's going to be hilarious.