I've never understood how the pods were supposed to work. Intrinsically, they have to take up as much room as a bed, or else you can't lie on them. But they can't be double-decked, else you couldn't sit in them. So you're locked in to a passenger capacity (hence cost per seat) comparable to a conventional sleeping car, for an inferior product that has to be priced more cheaply.
That, I imagine, is why Serco didn't make much effort to resolve the issues. They didn't want pods, but had to examine the feasibility. Likewise, they don't really want the seats, but can't get rid of them.
If there was a commitment to sleeper travel for the ordinary person, we wouldn't have Caledonian Doubles, and we'd have couchettes (32 beds to a coach) replacing two or three sleeping cars.
Three years ago I travelled each way between Bangkok and Butterworth (Penang, Malaysia), a 20+ hour trip, on Thai Railways "air conditioned second class" sleepers.
These have a central aisle, and as configured for daytime use, each side of it are 4-seat bays around tables. At night, they are converted like a caravan dinette, the tabletop goes down flat on the seat bases, and the seat and backrest cushions form a mattress, with bedding provided to form a wide single berth. A narrower upper berth is folded down from above the windows, and both berths have their own sets of curtains for privacy. I was concerned about security, but in the event there were family groups around me, and although I put my passport and cards under my pillow, I think it was actually pretty safe. The groups with children seemed to put (at least) two of them into one lower berth. There was an at-seat meal service, as well as local food vendors walking through at several intermediate stops.
They're obviously not as "premium" as having your own cabin, especially now CS ones include en-suite, but they seemed to be a good compromise between space, comfort and price, and I found them quite adequately comfortable and much better than trying to sleep in a seat. Thai Railways prices aren't comparable with UK fares, but I paid around £36 each way.
I wonder if this layout has ever been tried in this country, or if the UK loading gauge prevents it. They didn't seem to me to be much if at all wider than coaches here though.