Actually iOS is based on unix and you can get access to system with jailbreak and do a lot of interesting stuff. For example one of the really popular TMO users added support for android wearables for iPhone before it was released officially by Google :P

And if you say that he publish app to Stroe, you should remember that there are a lot of API limitations for Sailfish store even with available APIs :P

As of paid apps, there is huge thread on TJC that is few years old and was started by Jolla about paid apps, but as it get activity Jolla ignored it and any questions(again they started this thread, which is ironical). And after a huge noise from community on TJC/IRC/here/twitter they finally answered with "more info soon (c)" reply, as always

I think the paid app is one of the greates examples why I'm skeptical about Jolla for a long time. You can call me troll or that I'm bashing, but there are more than enough reasons for that, additionally there are certain patterns of them handling problems and using contradictionary PR(about how they are about openness but actually no info and only covering the problems).