If you want one example of why a lack of rotation doesn't work, look no further than Aston Villa under Martin O'Neill.
EVERY YEAR we'd play the same squad, the same 11 players and same 7 subs, and we'd fly up the table. Come Christmas, we'd be as high as second, and getting into the CL looked a done deal. And then you know what happened? It would all fall apart. Players couldn't press effectively, looked legged after 60 minutes, and were constantly in a state of semi burned out. We would crash in the league and fall to sixth, three consecutive times.
Not rotating is just retarded. And before someone gives me bollocks about 'excessive rotation', I did a little research a while ago, and there's a positive correlation between changes and league position, across all the top leagues. In other words, the more a manager rotates, the higher the club he's in charge of finishes. This holds roughly true for all the top leagues, but is especially relevant in the Prem; in other words, the league which has the most physically demanding football and most packed schedule.
Oh, and:
I would normally refuse to believe anyone is this retarded, but then again, this is the internet...