As someone noted, quarterly releases following the same slow-burn story progression would take us to 2023. Monthly releases would take us to 2020. So, if the idea is to somehow finish by 2020, but with ~quarterly releases, some story progression speedup is mandatory.
It's more a matter of WHICH story progression is sped up. Remember something like a HUGE speedup has already happened in 0.17 with the bj (a 2nd "new" sexual activity being outside the normal pattern of ONE per update) that was obviously meant for 0.18 if monthly updates had continued.
I'd prefer cutting daddy's harem adrift, but I doubt that will happen. Note that for some as-yet-known reason, the Melody launch tomorrow will be 0.01 AND 0.02. Something like that could be done with DMD with the next update being, effectively, 0.18, 0.19 and 0.20.