Well, my intent was to keep the question(s) as heartless as possible so as not to force the discussion along any specific paths, so your comments definitely hit the target.

Yes, this would be in line with the general benefits erosion we've been experiencing, though a bit more drastic than the death by 1000 cuts style (e.g. "Ahh, your lounge is over there in that corner, sir") that's been more typical. This is somewhat of a downer for us customers because elite benefits still constitute some form of tangible value, even in cases where airlines don't cooperate with each other. But, from the airlines' perspective, whittling down these fruits unfortunately seems to make sense; your ability to relax in a nice lounge in Singapore doesn't help United's bottom line.

Air Astana and MIAT are two airlines that seemingly could fill holes in any of the 3 alliances without stepping on toes of incumbents (i.e. previous threads on each). However, I increasingly wonder whether joining an alliance would make sense from an ROI standpoint (i.e. in addition to assuming new admin costs, they need to offer perks to more people, which harks back to your first point) unless they can somehow wedge their way into one of the alliances within alliances, of course.

Switching gears a tad, I've had several flights over the past year or so on alliance member airlines that seem to be barely hanging on. For example, I booked an EVA ticket from Boston to Taipei via San Francisco. On the SFO-BOS leg, I ended up flying Jetblue instead of United because the latter required a substantial upfare (using Alaska would have been the same price as B6 and Delta was only about $50 more, but B6 suited my schedule the best of those three). During my layover at SFO, I could have used the Polaris Lounge in theory, but that no longer makes logistical sense because EVA (along with SQ and maybe OZ, I think) has been relegated to the A Pier (the G-to-A connector wasn't open yet...still a long schlep even with it, though). And, of course, the other side of the coin has revealed itself in the United forum here, EVA doesn't exactly go to great lengths to comfort United passengers in TPE. Basically, now that United is tight shares revenue with ANA, EVA doesn't really bring much to the table. Similarly, EVA doesn't have much incentive to funnel customers to United, as long as United charges them more than the alternatives. This is somewhat related to your second point because any potential new entrants that overlap with existing members too much are likely to be second class citizens from the get go, IF they manage to secure admission.