Hi CDFinch,
You’re certainly correct about latex and memory foam being completely different animals … they are about as different as two foam materials can be (see post #2 here).
There are many people who prefer memory foam vs latex or vice versa but it certainly isn’t accurate to call one more “supportive” than the other or a “better” option than the other since this would depend entirely on the person, the specific design of the mattress (one mattress doesn’t represent an entire category of mattresses) and on each person’s individual needs and preferences. A mattress that keeps one person in perfect alignment (which is what support really means) may be completely unsuitable for someone else to sleep on regardless of which type of material is in the mattress.
In technical terms latex has a higher support factor than memory foam (also called compression modulus) so if anything latex would be a more “supportive” material and it’s the only one of the two materials that is suitable for use in support layers (memory foam is too soft to be used in the support layers of a mattress which is why all memory foam mattresses use a more supportive material or component underneath the memory foam layers) but in practical terms either one can work well as a comfort or transition layer and in the right design and combination of materials for a specific person can result in a mattress that works well in terms of PPP.
I think what you have discovered is that you prefer the memory foam mattress you purchased to the latex mattress it replaced and that for you it may be a better “match” in terms of PPP … but of course what works well for you (or any other person) has little to do with what will work well for the next.
Most of all though … congratulations on your new mattress. It’s good to see that you are happy with your choice :).
Phoenix