Hi gcrain,
You can read some of my thoughts about having more layers that can be interchanged or exchanged in post #2 here and post #14 here touches on this as well. There is a range of “needs and preferences” that is suitable for each person that puts them somewhere inside what I call the “I can sleep on anything” to “princess and the pea” scale. For those who are more sensitive to variations in pressure relief and alignment/support and may need to do more fine tuning or have a more challenging body type or circumstances, then more layers can provide more design flexibility and combinations of layering to fine tune ether pressure relief/comfort or alignment/support by re-arranging or exchanging layers and may be a significant part of the “value” of a mattress regardless of any difference in cost or any additional complexity that may be involved…
Phoenix