They should seriously work on creating official ports for other mainstream devices.

If I could run sailfish OS on a Z3Compact - I would pay to buy the OS

If they just sold the OS for a price for compatible devices, a lot of people bored with Android would buy.

Think PC/DOS sales model, v/s the Apple sales model b4 Steve Jobs

It required a Steve Jobs to sell the Apple model, I doubt Jolla has anyone remotely sales savvy