After two issues, DG sadly didn't go any further with their survey of the Steinberg Symphonies. Neeme Jarvi and the Gothenburg Symphony Orchestra did a splendid job with Nos. 1 and 2, so here's hoping the cycle of all five symphonies will be completed one day. (Maybe Jarvi can talk Chandos into recording the rest?)
I, too, have been frustrated for a long time that DG never gave us the whole cycle. Maybe there wasn't any interest. How many copies did they sell? And while the symphonies may not be earth shattering masterpieces, there is a lot of lesser music that is in the DG catalog. I would think that the Steinberg's are ripe material for Naxos. That great label has given us a lot of otherwise unknown music from the Russian school and Steinberg would seem a natural.