To some extent, yes. The manned flight ecosystem is not trivial. The tracking of info takes maintenance and really matters, safety wise.
That involves cost beyond the test, though I bet the FAA gets our tax money too.
Meanwhile, the drone people take the test and never bother the FAA again til next test.
So cost should reflect actual test cost, then service level beyond involved. We are like nothing after the test.
BTW, I'm sure the test cost prevents many people from taking it. If safety really was the goal, the cost would be low and everyone would e required to take it. Its not though, its about what the FAA was forced to do by Congress. They did something that looked good, fleeced industry, as if that was a good thing, and washed their hands.
The real safety issue of drone deliveries will likely not be solved for a long time, as they cannot solve the real problems, just the fake ones.