Let's say there is some expectation that the preview of files is expected by today's users.
That preview is usually handled by say Finder if it's minor and by apps when needed. There's now a big expectation of today's users that these views work but many users don't want to know how it all works.
So the OS does work fine without your noted apps but today's users may not want what happens when we remove apps. Again the OS is fine.
In the MAC O.S. system certain programs which should be non- essential are 'built' into the system so if they are removed the whole system might become unstable. Like Garage Band or Notes in the Mac O.S.X system ; if they are deleted even accidentally the whole system acts up. Shouldn't non-essential programs be independent of the whole system stability?