That does not make much sense. Most people who buy the season sets have already seen the episodes and know the resolutions. You are thinking of this from only the perspective of a fan.
This is not about cliffhangers. Its about creating new movies out of tv episodes. Movies can be purchased as an impulse buy because of a lower price and being able to watch it in a single viewing. Putting Spock on a DVD cover Picard and/or Data on sale for $14.99 is going to get attention.