I would also be forced to drop it if they were to switch to such a model. I would hate to do it, but I would out of principle. I have to pay enough in rent just to have a place to live and am not about to start paying to rent games too.
If ED really needs a future cash flow, then they should go make a clone of those P2P arcade flight games and put the subscriptions and microtransactions on that. Use the money gathered there to fund the development of DCS World.
And or charge a small fee for major version upgrades of the base software and major updates of modules.