Of course you can't sell a 14th or 15th place team in a league. Those are almost surely awful teams. You should be able to sell a 6th, 7th or 8th place team if you have 6 or more teams making the league playoffs. Just list the teams in order and draw a line at the playoff break point. It's easier to explain that to someone than "our team finished 2nd and the Red Sox finished 5th, but they are going to the playoffs and we are not." Fans only identify place in the division over place in entire league, because that is how it has been presented to them for years.
Owners might not like big divisons because many of them have made their fortunes largely by marketing to simpletons. However, the last time they discussed realignment, I remember that a group of players wanted to eliminate divisions because they wanted to assure that the best teams during the regular season made the post-season and they felt (probably correctly) the owners wanted divisions to water down league and make it possible to get into the playoffs cheaply with an inferior team. Players also were not in favor of expanding the playoffs further. So, I hold out some slight hope that the players might make this an important issue in future negotiations, although I understand it will probably just be used as a bargaining chip.