HI Cloud999.
You were quite fortunate to get 15 years of use from your Sealy Laguna mattress. As you well noted there have been many changes in the industry since you purchased it and … unfortunately, most of them haven’t been for the better (see post #3 here ). I agree with you that in the current market you’d be better off avoiding the major brands either because they use lower quality and less durable materials in their mattresses than many of their smaller competitors or … because of prohibitive pricing and because of making a blind purchase without knowing what materials it uses. Major brands do not list/provide mattress layer specifications as a way to discourage quality/value comparisons. I would certainly avoid any mattress regardless of the name of the manufacturer where you aren’t able to find out the quality and durability of the materials inside it to ensure that there aren’t any lower quality materials or “weak links” in the mattress (see the guidelines here).
Laguna Beach is a discontinued line manufactured by Sealy and attempting to find something that is exactly the same is often a frustrating and futile exercise especially when trying to do it on your own. There is more information in [url=https://forum.mattressunderground.com/t/christeli-much-firmer-than-expected] post #9 here about the different ways that one mattress can “match” or “approximate” another one. Every layer and component in a mattress (including the cover and any quilting materials) will affect the feel and performance of every other layer and component and the mattress “as a whole” so unless you are able to find another mattress that uses exactly the same type of materials, components, cover and quilting, layer thicknesses, layer firmness, and overall design (which would be fairly unlikely) then there really isn’t a reliable way to match one mattress to another one in terms of “comfort”, firmness, and PPP (Posture and alignment, Pressure relief, and your Personal preferences) based on the specifications of the mattresses (even assuming that you can find out all the specifications you would need for both mattresses you are comparing in the first place).
You are on the right track focusing on latex products … you’ve probably seen the mattress shopping guidelines with all the basic information, and steps that can help people make the best possible choice in the mattress shopping tutorial here, I’d especially made sure to go through the information provided in two of the most important links in the tutorial post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” in terms of “comfort”, firmness, and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) that can help one assess and minimize the risks of making a choice that doesn’t turn out as well as hoped for, and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help with meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to other finalists based on all the parts of your personal value equation.
Best of luck in your search for a suitable mattress.
Phoenix