Lotus have won two, and a race a year in 2012 and 2013 although they have lost significant backing since the glory. Force India, Sauber, Williams have won none in the same period, and only one of those teams have even won a race in that time.
I agree that a championship seems to have alluded them recently, and this season is poor, however, future howlers notwithstanding, of all the teams listed, and excluding Ferrari, Mercedes and Red Bull, I would personally feel more confident of race wins, and a potential championship at McLaren than any of the others.
I have lost faith recently, as they do not seem to be able to string a season together, but there seems to be moves in place to move forward.
That said, it would not be the first time I have been wrong!!!