343 did not move the franchise forward with Halo 4, according to many. So that put them on the back foot with a lot of people for their take over the franchise game. I don't think MCC was all that big of an issue. And then there was the widespread opinion that the SP campaign was disappointing. perhaps 343 underestimated the extent to which Halo players actually do care about the story and actually do play the game for the SP campaign. Possibly more than any other shooter, Halo is a franchise that has always been as reliant on SP as MP for its reputation.
I don't know how much loss of local split screen had a material effect, but it was yet another disappointment to people who are not primarily online MP focussed in their interest.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
