Group II+ and III are dino base oils, just incrementally better. We'll soon see Group III+.
Many oil products, like the new GF-4 and API SM motor oils, can be made from Group I base oil, but it requires a more expensive additive pack. More money will be put into the add pack than saved with the cheap base oil, so you're not likely to see much made that way. Unexpected events like a fire in a base oil refinery that causes a loss of Group II production could force some blenders to Group I temporarily...something like that.
And, many industrial lubricating oils will continue to be made from Group I base...works fine for that.
Ken