You are clearly right that both dPOS and Bitshares X is an experiment (remember, so was NXT, and so was Namecoin, etc.).
If Bitshares X fails, dPOS chains can still bloom. If dPOS fails however, things are looking more bleak. If that is the case, then either they copy the code of someone else and still get Bitshares X and the other products up. Or, if both of those options fail, they still have a lot of the funding tied up in BTC, so if BTC goes up, they can keep working for a long time yet.
Now, if dPOS works there will be a lot of buzz around the new technology, even with just a test chain. Plus, LOTTO, .P2P and whatever else will raise the market cap of PTS and provide lots more funds to work with. If Bitshares X even so much as shows promise on top of that I think we are going to da moon and beyond.