1) We started out long ago making a hiking website, which led to hiking iPhone apps, which led us to make all sorts of mapping apps, everything from Burning Man to hiking to driving. We basically now specialize in anything that takes an offline map.
2) The pricing model is based on some other successful apps - for examples, Wing-X in the aviation space and Motion-X GPS Drive. The .99 is not to make money, it's basically just to make sure you are a boater and are interested, and it helps keep costs under control for serving the data and using the APIs we pay for. We plan to eventually increase the 11.99 subscription fee, but people who subscribe early on will get to keep the same cost.
3) We did this now because Skipper is the forerunner of the next version of Gaia GPS, version 8. We have been working for many moons to overhaul our core code, and it will lead to 3 app releases. Skipper, Gaia 8, and one more for a partner I can't name.