My concern is that if WOTC launches 5e, they will immediately take down the current 4e character generator and monster generator to try to force customers to switch to 5e, and my subscription will become near-useless if I want to stay with 4e.
If it's really that much of a concern... then pay month-to-month.
You'd be spending an extra $4.00 each month to do so, but at least you'd know you could quit before anything happened to the Builders.
I think that a detailed piece of information like this is very unlikely to be made available to the general public. SJ Games is very open about their status (I'm sure that having a single owner helps with that ;-)), but I've never seen SJ reveal such details about one of their operations and WotC is far more tight lipped about their own business...Has anyone any insight on the ROI for DDI?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.