Yeah, the Netflix shows are staying put for now. What will happen after the announced seasons is anyone's guess. My guess is they'll stay on Netflix for at least one more season each (beyond the announced seasons, if they continue). That will take us to 2020/2021. At that point they may be wrapping up anyway, we'll have had 3 seasons of the 5 original shows (4 of DD) plus 2 of Punisher (assuming all continue). By then Disney will have a better idea of their own streaming service and whether it's worth the cost of moving them over or just continuing with Netflix (or ending the series).
Any new shows will be made for their own service. They've already confirmed a new Marvel show & a live action Star Wars series. That, along with a promised cheaper price than Netflix (to reflect less content) and Disney's massive back catalogue should make this worth checking out.
My plan with Netflix was just to sub for the months a new Marvel show came out, binge and then cancel, resubscribing for each new season. I've been subscribed since DD season 1
With Disney, I'm a massive fan of a lot of their stuff but that means I already own a lot on Blu-Ray so I likely will just sub and binge when the new shows go up. I'll be honest, they had me at live action Star Wars