The technology was always more or less "fine". Unreal Engine didn't "kill" Unity and it will not in the future.
For the better part of a decade, Unity tried to become not-sure-what but way more than "just a game engine", and that's the problem, I don't know exactly what and neither do they.
To be clear, Unity is not "dead" and will not be dead for a while, but the writing is on the wall with this "merger".
I'm not sure how is Boeing and who is McDonnell Douglas but I already wrote the off my mind.