I think I read somewhere quite a long time ago that Skype will stop supporting the library (Skypekit or how was it called) used by many 'Skype phones' which was also used on the N900 (and probably on the N9, too lazy to bother to check it now) and that they are focusing on delivering an official Skype app on those platforms that were utilizing the said library (or to stop support for the said platforms altogether).

Found it @ https://support.skype.com/en/faq/FA1...at-is-skypekit (you have to be logged in to see the page):

Skype URIs is just a control interface for the existing Skype client on any given platform and wouldn't cut the mustard here. Even if Skype was to ever arrive (natively) to Sailfish, I don't think that the integration we are longing for would ever be achievable via Skype URIs and it would require the full Skype app running in the background so...

Don't know if Microsoft is solely to blame for that, tho. It was rumored they'll kill support for Skypekit quite some time before Microsoft bought them (btw. I always like to compare the prices Microsoft paid for never-in-their-history-profitable software company and the whole D&S department of Nokia including granted patent use, factories, offices... but I digress) - they were in the process of introducing advertising in a vain attempt to earn something which just wouldn't be feasible through the library, thus - discontinue the library! Microsoft even went on to say that they are interested in having Skype on every single platform out there and that Skype will be not hindered whatsoever after their purchase of it. I know, timeo Danaos et dona ferentes, but still...

Anyway, I wouldn't rise my hopes of getting native Skype on Sailfish anytime soon and given the current state of things I don't think we'll ever see the level of integration of Skype we've experienced on the N900/N9