Hi cope,
I’m glad that you’ve become educated so as to be able to discern between different marketing ploys. Regarding mattress durability, while there is no way to know for certain how long any mattress will last or maintain it’s comfort and/or support for any particular person or how long it will take before they cross the thresholds between sleeping well on a mattress to sleeping “OK” to tolerating a mattress to finally deciding to replace it because there are too many variables involved that are unique to each person … if a mattress is well inside a suitable comfort/support range and isn’t close to the edge of being too soft when it is new and meets the minimum quality/durability specs that are suggested in the guidelines here then it would be reasonable to expect a useful lifetime in the range of 7 - 10 years and with higher quality and more durable materials like latex or higher density memory foam or polyfoam (in the comfort layers especially) it would likely be in the higher end of the range or even longer.
It is true that finding a local latex retailer can be a bit more difficult, as properly explaining and selling latex generally requires a more knowledgeable sales staff, and unfortunately that can be a bit difficult to find in this industry, especially in many of the larger chains. As far as “overmarketed”, I’m not sure as to what you’re referencing, as latex tends to be one of the “lesser known” types of mattresses here in the States. If you mean “overmarketed” as referring to some of the claims and “greenwashing” that some stores and brands use, that unfortunately can be the case, as it is with many other mattress types in the industry.
Make sure that when comparing you are aware of whether you are testing out Dunlop or Talalay, as they each have different qualities of comfort. I’m assuming SleepEZ already gave you some good guidelines regarding this. I do trust their advice (they are a member here of the site) and knowledge regarding latex and “matching” their items as best they can to models you may test elsewhere. You are correct that latex will generally be one of the most durable products available, and in the long run can represent a very good value as well.
Subject to first confirming that any retailer or manufacturer on the list that you wish to visit is completely transparent (see this article) and to making sure that any mattress you are considering meets the quality/value guidelines here … some of the better options or possibilities I’m aware of in and around the Dallas/Ft Worth area are listed in post #4 here.
Phoenix