Yeah those apps were my inspiration: use the native UI and share logic as a lib.

I don't even have a Mac yet, so no point in shipping for that if I can't debug it.

If sales are good, I'd be glad to buy a cheap macbook off ebay and port it.

Even better if the library code is properly written, not only you can have multiple GUI frontends, you can make the CLI folks equally happy, and most of the code remains portable.

Naturally nowadays this is too much to ask for, so many ship the Chrome Application Platform instead.