Very few would actually need it, and by the time is becomes the norm to tap into that amount of RAM while computing the rest of the MBP will have dated.
Get 16-32GB now, and 3-4 years down the road when 64 is the new "32" you switch over to 64GB and also whatever new processors and graphics are out at the time.
Get 16-32GB now, and 3-4 years down the road when 64 is the new "32" you switch over to 64GB and also whatever new processors and graphics are out at the time.