Indeed, there is more competition now, however, given this high level of competition, Vettel is still able to come away with one of the most dominant seasons in F1, ever. That says a lot: team and driver are working very well together.
Providing Vettel can continue to drive a car which is at least competitive and capable of winning races, the guy has every chance of attacking MSc (long term) records.
The other point of note IMO, is that Vettel is still getting better, so there is no reason to believe that he has now reached his peak (where Alonso and Hamilton do appear to have peaked). I think there is still more to come.