You keep saying that, but you haven't said how many more small companies are involved than big companies. If it's 100 times more (and I'd expect it's more than that given the likely scalings), then you're not making sense.
You’re assuming that the effort required grows at the same rate as the number of companies. Perhaps that would be the case if it was all the gap needed prosecutions to fix. But if it’s more likely down to errors etc. (as you claim) then solutions could be put in place that help many more companies meet their tax obligations.