They will never implement vertical sticky scrolling.
My guess is if they do try some scrolling feature it will be HORIZONTAL month to month 'scroll' with your mouse wheel.. essentially just mimicking the month forward and back arrows, jumping month to month. Not sure who these people are behind the user interface, if they are getting feedback, or what their thoughts is on this issue. It's not technically difficult and they can do it without issues... question is why they don't at least offer scrolling as an OPTION for those users who want it, Just a simple toggle in settings to allow scrolling. My honest suspicion, there are some egos involved and probably someone on the team high up refuses to allow this and gets offended when others suggest it. All this feedback probably making him/her more annoyed and more intent on never including this option. User feedback probably went from 'this is what users want lets make it happen' to 'how dare their question our decisions'. There really is no other reason.