As others have mentioned these workers have so little leverage right now because of the massive unemployment. So even if Amazon was to charge customers more, they could totally just pocket the money and the warehouse/delivery/grocery people would have no position.
It's so completely unfair. Everyone risking their lives to feed us right now should probably be making 2-3x normal pay (and we should be paying a lot more for their services).
This makes less sense if you're one of the tens of millions of people making much less right now.