Too early to sing "Champions"?
How does that make it a on-horse season?
There's a point at which it becomes really obvious who is going to win the league and it's rare that point comes right at the end or goes down to the last game. United had the title wrapped up the moment City started to bottle it in the new year (as they were the only challengers) - at that point it became just a case of how big the gap will be. As good as Spurs and Newcastle have looked, they were never going to be contenders - the table is roughly the same every year at the top for a reason. It's 8 points now and given the way they're playing it'll probably be more like 11-15.
Given the last team to win the league other than United or Chelsea was us a very, very long time ago, we've had plenty of time to see how United might have an iffy start but they will always consistently get enough results to accrue a title-winning points total:
they set the bar, which is usually too high for anyone else to top. When Chelsea have won the league in recent years, it's because they managed to be even more consistent than United, which is no mean feat.
City's consistency ended in the new year around the time of the ACON and their dip in form has gone on way too long for them to finish strongly. They've taken our mantle of a strong start and woeful finish.

Does anyone really think they will win all their remaining games playing the way they have recently?
The moment United overtook them, they never looked capable of leapfrogging back. How many times in recent years have these Super Sunday type matches between big teams near the end of the season been played up as deciders by the press with weeks to go, and by the time they actually happen, the result has become irrelevant as large gap has opened up.
/DM post
Cliff Notes - United are consistent every year. City stopped being consistent weeks ago. Therefore City have no chance of winning the league this year.
Also,