Simple...
Alonso and Renault deserve the title. Kimi deserves fight until the end and even win...but, Mclaren-Mercedes don´t deserve win the constructors champioship by now...not at all at the moment.
There is no use to have a car that is the fastest, but last only 30 laps, or broke even before the race, in practice or something. It has been happened to often...
It doesn´t matter if is Kimi´s car or Juan Pablo´s car that broke, the fact is that Mclaren-Mercedes broke.
Alonso do what is necessary to win a champioship, he is very mature, even to the point of saying that finish third it´s not so bad if the title come his way, whereas Mclaren and Kimi talk only about wins and more wins, but they seem incapaple of take the wins that they say they deserves. Kimi may well deserve...Mclaren-Mercedes no.
To risk everything in order to win maybe it´s not the way to go. Score strong regulary, always being competitive and fighting for victory, without put everything above the limit, it´s what win a champioship.
By the way...Ayrton Senna wins 3 WC with Mclaren because sometimes he accepted to finish second, third, even fifth...just to score importants points, instead of risk everything for the win....especially in this Third champioship. Alain Pros it´s also a excelent example. Prost beat Senna in 1989 because he was more regular, whereas Senna only was going for the win, and by losing to Prost, learn how to do it.
Kimi maybe knows how to do that, but he wasted a race in Nurburgring, sometimes it´s seems that he´s just push to hard. Mclaren and Mercedes could control that, but, seems that they are not trying...