Right. Including the invisible fees (due to increased BTC supply accruing to the miners), a transaction right now costs around USD 100. As the mining reward dro

Right. Including the invisible fees (due to increased BTC supply accruing to the miners), a transaction right now costs around USD 100. As the mining reward drops, either miners make less (good, they'd stop wasting), or fees paid by the user would have to increase substantially. If users don't pay up, there'd be much less hash power devoted to the system, rendering it insecure.