Hi FAUguy,
This is the norm in the industry and the main reasons that adjustable bases aren’t returnable are because they are very heavy and costly to return and because they can be used under many different mattresses and aren’t specific to a certain mattress so even if you exchange or return a mattress the base can still be used with a different mattress. The biggest reason though is because it’s not part of their return/exchange policy that you agreed to when you purchased it (you can see their return policy here). The cost of return and exchange policies are always built into the cost of a product because the people who don’t return a product are the ones who pay for the ones that do.
The first place I would start your research is the mattress shopping tutorial here (there is a longer and a shorter version) which has all the basic information, steps, and guidelines that can help you “reset” how you are looking for a mattress and help you make the most suitable, the most durable, and the best value choice … and perhaps more importantly know how and why to avoid the worst ones (including major brands or mattresses that have too much lower quality or unknown materials or “weak links” in their design such as the Aireloom or Prana mattress you were considering).
Two of the more important links in the tutorial are post #2 here about the different ways to choose the most suitable mattress (either locally or online) that can help you identify and minimize the risks involved with each of them and post #13 here about the most important parts of the “value” of a mattress purchase that can help you make more meaningful comparisons between mattresses.
Once you reach step 3 in the tutorial then if you let me know your city or zip code I’d be happy to let you know about the better options or possibilities I’m aware of in your area.
Phoenix