Hi Napper,
There is more about the pros and cons of one sided vs two sided mattresses in post #3 here and the posts it links to.
An “old fashioned” two sided tufted innerspring mattress with natural fiber comfort layers would certainly be a very durable choice but it will also tend to be firmer than most mattresses that use foam materials in the comfort layers and natural fibers will tend to become firmer over time as they compress and pack down to some degree while foam layers will tend to become softer (particularly under the heavier parts of the body) over time. Some of the comments in post #4 here and post #2 here may be worth reading as well.
Wool is also a more resilient fiber than cotton and will tend to pack down less and maintain it’s softness and resilience better than cotton batting over the course of time.
They tend to be very good in terms of temperature regulation as well.
Phoenix