I think they are focusing on the van life market. Might be more profitable than the pickup truck market. Anyway they are still in business just doing something else. I'd guess the Sprinter, Transit market is huge with few players.... the 4WD pickup market is saturated and not growing.
I'm sort of surprised how little is out there for the Express. I know, relatively speaking, most folks seem to prefer the E-series but, frankly, most of the newer vans, well, I just don't have confidence in them taking much abuse in terms of unibody/ladder nor the the smaller engines and turbos. And the Express is still in production.