True, but acknowledging that backward time travel is valuable (the future-lightcone of past-you has a greater volume than the future-lightcone of current-you) isn't the same as having a time-based discount rate; the former is based on instrumental reasoning, whereas the latter is intrinsic.

I suppose I've always seen time-based discount rates as a shorthand to encode the instrumental consequences of the past occurring before the future. Resources can be compounded, external resources can also compound, and memories seem like a special class of resources worth paying extra attention to.

So, that is, even if you deleted the discount rate of x% a year for having resources in whatever year, you would still have to address the hypothesis that the way to have as much legally acquired money as possible a year from today is to transport your seed resources as far back in time as possible.