It is a theory.. I have three good theories myself.
One problem is the money went to Cooper in packets of 100's rubber banded into bundles.
So, the individual packets of 100 bills were not separate in the bag, if they did arrive on TBAR separate, somebody had to have removed them from the rubber banded bundle. Therefore, it is more likely the money arrived as one rubber banded bundle of packets. You don't need a bag/container to reconcile the money arrival.
The other problem is the LZ, the evidence does not support a Columbia River landing.
There are infinite theories and possibilities. We will never know the real story, but some theories fit the evidence better than others.
If I had to bet, based on all the evidence, Cooper landed near Heisson.. but we will never know for sure.