Hi Luciusg,
You can see my comments about “wire grid” support surfaces for mattresses that have a latex support core in post #10 here. The simple life foundation would certainly be strong enough for an all latex mattress and would certainly be suitable for a mattress with a polyfoam support core but I (and other manufacturers I have talked with) share your concerns about the longer term risk of these types of support systems for an all latex mattress although it may also be an “overabundance of caution”.
There is more information about the different types of support systems that are generally most suitable for different types of mattresses and some good sources for each of them (including some KD or “knock down” foundations that can easily be assembled or disassembled) in the foundation post here.
Phoenix