I agree! Look at the Cleveland Cavs right now, you think their fan support wains after a loss on the road? Perhaps, but do half the fans stop watching? No. I think if you're traditionally a poor team and you lose a close game on the road to a much stronger team, that should increase fan support.
Some poor guy in my league is getting creamed so far and he still has to play me twice on TV this year. If he gets within 10 points, his fans should be happier.
Does the formula currently factor in relegation and promotion? Realistically, I hoped to go .500 my first year in a higher division and I think that's accurate as to what the average fan expects. Anything over .500 or the playoffs should be 4 or 5 balls easily.
On that note, if you're relegated, your fans should expect promotion that year and a first place finish. Kind of like fans in the English Premier League.