Although paying off a loan to your 401k most likely comes from post-tax sources, if you merely wanted to move more money into your 401k than would otherwise be possible, doesn't this accomplish that?
Since the 401k is a valuable entity in own regard, there can be several reasons why it would beneficial to get as much funds as you want inside of it.
The higher the interest rate the better, so it seems that - in this scenario of merely wanting more inside of it - it is worthwhile to have at least 1 loan being paid off of a 401k any given year. Since ideally the value of the 401k will also be going up from normal contributions and market appreciation, the next loan can be bigger. The best scenario seems to be paying off a $50,000 loan annual.
This math exercise is intended to be independent of the average salary of the population.
A) Does this accomplish the goal of routinely getting additional funds into a 401k?
B) Could one force the interest rate to be much higher than prime rate?