When the program was started, the minimum salary was set at $60,000. Adjusted for inflation, it would be $110,000 today.
Not many bachelor's degree programmers with less than 7 year experience make $110,000.
Any fixed value we set it too would quickly become cheap again due to inflation.
So we need to set it at a quintile. If we said that H1B's had to be paid a minimum of top 10% income, then companies would only import workers they really needed (as was intended).
However, the cow is out of the barn. If wages go up in the U.S., many companies will simply offshore the work. Try to ban it, and they'll set up "separate" companies under the corporate umbrella offshore which do the work.