History says otherwise. Properly sized SSDs (~2x necessary capacity) seldom wear out in 4 years as long as RAM remains adequate and the OS is not constantly paging to SSD.
RAM demands OTOH always inexorably increase as OS and apps start asking for more. My past experience puts that point where max-originally-available MBP RAM becomes limiting at about 3-4 years.
Note also that I do not identify RAM as becoming "obsolete," rather it becomes more and more limiting as the OS is forced to swap to SSD, slowing operation and dramatically accelerating SSD wear.
Some buyers, perhaps most, cheap out and install the RAM they need today, which IMO is flat dumb. Smart buyers buy for expected RAM needs toward the end of whatever life cycle they plan, not for the beginning.
Note that buying less RAM may force your statement "MBP will die of SSD wear faster than 96Gb RAM (even 64Gb) will become obsolete" to become true, especially if both RAM and SSD are undersized. Personally I consider the headaches of dealing with worn SSD and later-life-cycle performance limitation of less RAM far more significant than the cost of initially oversizing both RAM/SSD.