So, is this a valid concern? Will the cancellation of 4E support via Insider have much impact on those currently playing 4E? Are groups planning ahead for such an eventuality, and if so, in what way?
I'm sure there are groups that would be heavily impacted if they turned off the 4e DDI material. But, we should be clear that this is the choice of those groups - the print options are available, but they haven't chosen to buy.
Finally, what about 5E and technology? If more and more gameplay (and game prep) are moved online, and can be cut off any time the publisher desires, how much will that affect your decision whether or not to purchase the game?
My players vastly prefer not to have electronics at the table. They've said they don't mind if I use a laptop for reference and SFX, but having a ring of laptops around the table is not an option. So, if 5e cannot be well-played without electronic support, then they can kiss my cash goodbye.
But, honestly, I don't expect them to go that route with 5e. They'll design a game that can make really good use of online support, especially for the GM, but I expect it'll be a perfectly good game without that support.