Depends on who the backers are I guess. Perhaps not the classic kind — like say, convince MS, Apple, and Sony to pony up $10mm each. It’s a good play for them to not be caught in this Unity fiasco and $10mm is a rounding error.
The devs using the OSS engine also wouldn't be stopped from spending resources on making the engine better for their uses (and in turn, making it also better for everyone), similarly how it works with Linux.
And you wont manage to achieve anything with that. Maybe Unity could spinoff its ad business (together with some major liabilities like Ricitelo and other execs) and then MS could buy the engine part.
Realistically that would still only be enough to get something you can make a cool looking demo and that only run on desktop.
Building a general purpose engine that is suitable for many different workflows and run on pretty much every singe platform like Unity is very trick and takes a lot of time (and trial an error). Dev UX, APIs, platform integration, QA, all the third party packages and infrastructure are much harder to solve than shiny graphics or advanced physics. Whatever you come up with that $30mm is only likely to cover a small subset of use cases.
$30mm is more than enough when you ditch legacy stuff like anything that isn't a Vulkan/DX11/Metal renderer.
With the right team it might. Realistically they'd just under promise and undeliver (or not deliver at all).
> stuff like anything that isn't a Vulkan/DX11/Metal renderer.
That's also not the complicated part.