Hi paisley,
I don’t know the ILD of the base layer in the Aloe but they could probably tell you.
In general though … the IFD of polyfoam will be firmer than the ILD of latex because one is measured on a sample that is only 4" where 25% compression is only 1" while most latex is measured on a 6" core where 25% compression is 1.5". There are many other variables as well as you can see in post #6 here or in post #4 here.
In other words … even if the ILD was measured the same way it would only be a meaningful comparison if you happened to sink into the layer by exactly 25% and there are more factors involved in how firm a foam feels or how it performs so ILD/IFD comparisons can be somewhat misleading.
There are many factors involved in the durability of a foam which you can read in post #4 here but there is no way to attach a number to any specific foam because it depends on so many things (including the person on the mattress). In most cases a foam doesn’t “wear out” or break down completely before the mattress is replaced because the gradual loss of comfort and support will gradually take you over the threshold and outside of the range that is suitable for you even though the foam may not be “worn out” and may be fine for someone else.
Having said all that … the support layers are not usually the weak link of a mattress and they will last much longer than the same materials in the upper layers so a good quality polyfoam base (such as the 2.17 lb polyfoam used in the Aloe Alexis) would normally last 10 years or more yes (again depending to some degree on the specifics and design of the mattress) … even though the layers above are subject to more stress and may soften or break down more quickly (which is why it’s a good idea to have a more durable foam like latex or other higher quality foams in the comfort layers)
Phoenix