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).
I think we're seeing the market work exactly as intended. It goes both ways. If workers strike (with solidarity), the market will respond accordingly to find a price at which people are willing to do the work. But no, it won't happen instantly. The capitalists won't just give in and say "You're right guys, we're sorry.". Their hand must be forced, and that is the history of all organized labor.