It indeed is their problem since it’s them that had the “genial” idea of introducing M+ in this form (basically the timer, let’s not joke each other more please, 99% of “issues” are caused by the presence of a timer).
It is indeed their problem if majority of people get to a point in which they can only use their key or they cannot progress (tanks aside, maybe).
And having reached myself almost 1200 rio with soooo little spare time means that the major difficulty is not doing 15, is GETTING into 15 even if you have the prereqs (no, prereqs should be the same you should have to move from 10 to 11, asking for 1300 rio for a 15 is just bad game design).
Don’t get me wrong, I fully understand your pov, it’s simply not mine
Peace.