So far though just to give you a comparison I've spent $0 on unity and $45 on the toolkit I'm using for it and have yet to be forced to create a minimalist project or else have my bug report dismissed by either the toolkit dev (one-man team, less customers than Scirra I'd imagine though) or Unity devs.
If you want to compare things, go all the way.
In your example, the toolkit you refer to is a third-part developed tool that is built upon Unity's main framework. In C2's framework, that is equal to third-part addons developers (like Q3D plugin). That is not C2 itself, and is far from the same complexity as far as support goes.
It is "easier" for them to check if it is a bug of their own plugin indeed, since the global framework does give debugging tools, as well as the already general present debugging tools in browsers. Also, the toolkit/addon has a smaller scope and it relies on the assumption that the main framework does what it is supposed to do.
An addon is a modular smaller part of code that is "separate" from the main framework, and works in relation with that one.
Unity team is bigger than Scirra's, so they have more resources they can devote to "support" and as Ashley mentioned possibly look further into any project/bug report.
And let's consider any user sends their 300+ events project with barely any structure or comments for review to Scirra.
After taking time to figure out what the project is supposed to do, how it was made, it happens that it is a user mistake, that is time that was wasted for everybody, except the project's owner who got someone to freely fix a mistake of theirs for them.
Nice for Unity if they can afford that. I understand though that a small structure like Scirra can't afford it. Don't you ?