Considering the population you really can't knock 343i for their relentless sustain of Halo 4. I think they should be proud of that fact and Halo fans should take that as a tick in the win box somewhat.
[paraphrase] "Regardless of the population, we should just be thankful that 343i's doing something at all!"
The reason the population is small in the first place is their mishandling of the franchise. The fact that they're still attempting to correct their mistakes - and they have yet to fully - almost a year after release, what does that say?