Big profits from mobile games are always going to turn the heads of investors and board level management. Hopefully there are sensible people shouting about the fickleness of mobile game revenues at them every five minutes so they don't lose sight of the core business they need to maintain.
His evaluation does seem completely off kilter though. There are lots of reasons why they didn't hit the target - chief of which was "it was too high" - but to admit that he would have to take blame directly himself. I think "insufficient efforts to convey it's appeal" is hopefully just fluff to give a reason and they actually understand the market a little better than that would appear to suggest.