Hi Sleepless,
100% NR talalay has been available since early 2005 (at least by latex international). I’m not sure when Radium started producing it but it would also be “relatively” recently. The NR talalay version was more in response to consumer desire for more natural materials rather than a desire to produce a “better” or more durable material. The talalay process itself has been around since the late 1940’s. Most of the “decades old” stories about latex mattresses would be from Dunlop single layer mattresses which were commonly sold as single layer mattresses or from blended Talalay.
I certainly believe that the BE coils are durable and would hold up for much longer than 10 years. If anything … the NR talalay in this mattress would be the “weakest link” although I would expect that it too would hold up for 10 years or longer and like you say can always be replaced for far less than the cost of a whole mattress. I personally like the NR talalay in terms of its slightly greater elasticity and feel even though I know that it may be less durable than the blend.
All in all … the BE is a good choice IMO in terms of materials and durability and the only way you may be able to do “better” in terms of a mattress that fit your preferences and needs would be through other independent manufacturers which use similar materials in their mattress.
An example of a similar mattress is the Diamond Maple Hybrid which was under discussion in this thread. There are some similar style mattresses (although not exact duplicates) made by one of our members (Parklane in Washington and Oregon) here as well for reference.
Phoenix