Well I completly disagree and if that really happens which I doubt the only reason is because of the boring nature of a static campaign - IMO, there's no point playing a static campaign (and nowadays every combat flight sim seems to have static campaigns only). IMO it's preferable to play single missions (specially of the sim support user made missions) instead of a static campaign since in single missions you can choose which mission you wish to fly (as opposed to a static campaign).
If you take a closer attention, the vast majority of people play older sims such as Falcon 4, EECH or Over Flanders Fields (even if this last one isn't "that old") because of their dynamic campaigns.

I also have enormous time contraints (for playing games) but IMO the time that requires to play ONE campaign mission is exactly the same or very similar as the time required to play ONE Single mission - The diference is that in a dynamic campaign a mission that you play will somehow affect the next one and this makes all the diference!