Well, this is a question that I feel can only be answered with, basically ..., an "It depends."
Maybe the wood will rot, and is doing so on the outside (which you can't see.) Maybe it will be fine. I'm not sure what a Contractor does to 'sure up' a wooden foundation but if it's not sured up 'properly', then it could 'collapse'. Look at how the home has settled. See if there are still cracks occurring. Look at how doors and cabinets open and close. (See below about having your Inspector do these things too.)
Have you had the home inspected? Is your Inspector one that has EXPERIENCE in inspecting this type of home? If so, I'd get a reference or 2 and visit those folks and talk to them. If the Municipality gives a Certificate of Occupancy, that should be helpful. You can talk to them. You can talk to the original Contractor AND the Mfgr. for info. Maybe they know of an Inspector. This is why they're done.
As for a concrete block foundation, they're fairly strong ASSUMING they, too, are 'properly laid'. And the same goes for a poured foundation.