I don't think the current FP+ is it, because FP+ still doesn't assign a specific amount of revenue to a specific ride. Not at all the same as a customer choosing to spend some real cash to get on a ride. Of course the bands "could" be used for this, just tap to pay to get on a ride (and then enter your PIN, it's so efficient).
Actually thinking about it more, this idea may have had its initial trial at DisneyQuest. When DQ first opened, you paid to put an amount of value on a card, and you swiped the card at each experience to deduct value from the card. Each experience "cost" a different amount, which was deducted from the balance on the card. I know that doesn't sound like much today, what with rechargeable store cards and gift cards being so common, but it was pretty innovative for the time. The cool thing about those cards was that you could swipe them in any orientation.
My strongest recollection about the interaction with Tony that long-ago day was the look of total disappointment on his face when he saw the aghast reaction he got from everyone there at the notion of going back to paying for rides. I suspect that that reaction was common, and may explain why this was never implemented in the parks.