It's probably <<10 cents in quantity though and most mass produced electronics would use something smaller or more efficient (well, it has to be more efficient

It's probably <<10 cents in quantity though and most mass produced electronics would use something smaller or more efficient (well, it has to be more efficient if you want to go smaller) if they even use a linear regulator at all. What would the total world wide market for 7805 be today? A few million parts a year? As a counterfeiter you'd have a few % of that market? Maybe worthwhile as part of a larger counterfeiting operation if you have the flexibility to make a lot of different chips in a lot of different packages but investing a lot of engineering effort in this specific single chip is almost certainly not worthwhile.