Mostly sailors are very conservative and the technology has to be bulletproof. The saying goes that Murphy was an optimistic sailor. Plotters are a marriage of RADAR and paper charts. The technical integrations are really no trouble for the average system administrator. The problem comes about with the challenges of the environment and the uniqueness of every installation. The market is also small. I think the estimate is around 10,000 yachts actively moving around the world.

Another issue is that there are very few makers or the technology.

I think it's a great area for development because it is immature and in the middle of technical upheaval that nobody really knows what how great a plotter could be.

Making CarPlay for boats would not be so hard, but making Waze for recreational boats might be. But if you have ideas on that and are sure you can avoid directing people into deadly obstacles, considering all sea and weather conditions, in all kinds of boats, give it a go!

All commercial plotters have autorouting. There is automatic wind routing for sailing in OpenCPN (as a plugin). I'm not sure that adding it to a phone with carplay is a viable option. If you have a display to show it on, it's probably a display for a plotter with all the functionality, including map updates over the internet.

Thou for entertainment it's an other side, that would be useful.