In my opinion you have to see whether you're an "Risk it all" person or you want something over time.
I'm making an assumption here and maybe a numbers guy could boost or sink my argument. I believe that movie's are "risk it all" ventures, whereas the series are safer. I would argue that the money made from one movie doesn't come close to the money made from a series. We see box office and some of the perperphrial sales in movies, we see almost nothing in T.V. But my guess is that between add sales at the time of the series, DVD sales, merchandising (from the Toys to the Trek Conventions) that TNG, DS9 and/or Voyager outsold the best Trek movie, which I think moneywise is still Khan (adjusted for inflation).
Beyond the money though, when Trek, DS9 and Voyager ran they had a pretty decent lock on the media market. We talked Trek and wanted Trek all the time! If you just focus on the movies, well, Trek isn't Star Wars. I don't know if movies, unless they're big box office - which hasn't been the case of the Trek franchise, will keep Trek alive. I believe that without a series "OK" movies and novels won't keep Trek alive, but only on Life Support.
I'd also point out that the Trek the majority of people love the most is the TNG universe Trek which encompasses TNG, DS9 and Voyager. Another series set in that timeline, with maybe even a few actors from the old Series, I think would be fun. But I don't know.
Fear leads to anger. Anger leads to hate. Hate leads to suffering.