What let the latter two movies down as poor writing. Generations was good, whilst First Contact was very good.
IMO, Insurrection could still have been a rebellion movie (as obviously the title suggests) but tie it to the Dominion War. The fact most regular Joe movie goers had never heard of the Dominion matters little. Films sell big via promotion. If it's promoted that Picard and co. were at war, then it could have worked, and had a knock on effect on DS9. That would have been to Paramount's benefit, since DS9 was not a lucrative end for them (despite a high outlay).
Nemesis could have gone as thus. In the Mirror Universe, the Terran Rebellion has conquered the Cardassian part of the Alliance and wants to steal some "real" universe Starfleet ships to conquer Qo'nos. To this end, the mirror Picard transports over to the real universe and duplicated the real universe Picard. The nemesis then is the mirror Picard, since the goal of the Terran Rebellion is to destroy the mirror Qo'nos, as punishment for them being enslaved by the Klingons. Again, proper/effective promotion could have drawn in persons to see it.
Does anybody remember the Blair Witch Project from years ago? I think the only reason people went to see it (since the movie stunk
to high heaven) was because of how it was promoted. Film promotion can make moviegoers see anything.