Pat, I have publicly asked this question of Jeff. He stands firm that other chart apps will continue to work with Active Captain--the product he sold to Garmin. He pointed out that there was a new app being released with charts and Active Captain. I still have Garmin Blue Chart App, and I have not tried the new app with my charts due to health issues (have to take my plotter and put it into the boat, to get the unit ID number (different than serial number),. My 2 year old Garmin 10" plotter will not do all of the functions of the new Garmin ActiveCaptain app--but should do some. I think Greg has done some experimenting, and I know of several who have recently bought the chart plotters which series ends in a "2", where they should be fully compatible.
As I understand it, you can still use the Charts on "Garmin ActiveCaptain App", but would pay for the charts direct. If you have the Garmin Chart plotter then you use the maps which are on the chart plotter--and should be able to update them--there may be a fee?
I don't have time now, but I will look up and check all of the other apps which use Active Captain, their cost and availability.
Navionics, which is now owned by Garmin, will continue to be "independent"--although I suspect that their database will be used to update or improve Garmin--and be available to use on Raymarine, Furuno and Navico product lines.