Hi Louise,
Hopefully you’ve had the chance to read the mattress shopping tutorial here which has all the basic information steps, and guidelines that can help you make the best possible choice … and know how and why to avoid the worst ones.
You’re certainly right that the industry has changed substantially in the last 20 years and much of it isn’t for the better (see post #3 here and post #404 here).
Inerspring mattresses are generally a very durable mattress component but the quality of the foam above the innerspring is generally the weakest link of the mattress and mainstream mattresses that use lower quality materials in the comfort layers is the biggest reason for the early softening, sagging, and breakdown that you can read about so often … not the innersprings itself. An innerspring mattress with high quality and durable materials above the innerspring can be a very durable choice.
I would also be very cautious about using mattress reviews (positive or negative) as a particularly meaningful or important part of your research (see post #13 here).
Unfortunately nobody else can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved in a mattress choice for anyone to be able to tell you what to choose or predict which mattress will be the best “match” for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) based on specs (either yours or a mattress) or “theory at a distance” (see mattress firmness/comfort levels in post #2 here) but the tutorial post has much more information about “how” to make a choice that is “best for you” that will give you the best possible chance of making a successful purchase.
There is also more in 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.
Unfortunately there aren’t a lot of great options in the Durango or Farmington areas that I’m aware of (see post #2 here).
The better options or possibilities I’m aware of in the Albuquerque/Santa Fe area (subject to the value guidelines I linked earlier in this post) are listed in post #5 here and the list for Colorado Springs/Salida/Pueblo is in post #3 here. Since there are so few good options available in your immediate area it may be worthwhile considering a visit to these areas or perhaps an online purchase would also be worth considering. The tutorial post includes two links to lists of the better online options I’m aware of (in the optional online step).
Phoenix