Why are you treating this as zero-sum?
It then becomes the problem of its users, and rapidly the problem of userland developers, because users expect their software to just work in Ubuntu.
Developers can now go and waste effort just to comply to Canonical's de facto walled garden, or lose all Ubuntu users (furthering the "Linux is too complicated and fragmented!" narrative).
Everybody loses, nobody wins.
Assuming source distribution, I do not see any special effort required.
This is a protectionist, anti-choice argument.
No special effort to support Mir/Unity/upstart? Other Ubuntu-only APIs, standards, UX, Kernel/Library versions not employed by other distributions, …?
(Upstart was killed when even Canonical realized it was impossible to demand of everyone else to support their special snowflake init system.)
It's also funny how people routinely bitch about Upstart when it predated systemd.
Would you be able to elaborate on this a little bit? It seems like a contradiction to me but it's more likely that I'm not understanding properly.
Canonical depends on their community for everything from the very OS (Debian) to marketing to support.
Yet, they're crippling their community at the same time with their IP policy and their general refusal to integrate with software projects they depend on for survival.
This is, simply, unsustainable. Canonical cannot fork everything and do their own thing (not without quickly going bankrupt – unlike Apple, which has no problem with say, developing their own SMB stack if needed); and they cannot continue alienating potential (and current) users and upstream sources.