Hi Rjannelle,
I certainly wouldn’t agree with him and in “real life” the layers would only be rearranged or exchanged in the first few weeks or months of use when people were making adjustments to the mattress to find the best combination of layers in terms of PPP. Once they found the most suitable combination then they wouldn’t have any reasons to remove or change the layers. One of the advantages of a component mattress (outside of the ability to customize the mattress after a purchase) is that you can access and replace only a single layer if one of the layers (usually the top one) softens or breaks down before the others without having to replace the entire mattress.
Durability certainly wouldn’t be a concern with any suitable latex mattress.
There is more about the pros and cons of two sided mattresses and one sided component mattresses in post #3 here and the other posts it links to.
Phoenix