>I think you are overestimating the inconvenience of paying at or near the destination. Most passengers will have smart phones with them, most of which support NFC payments.And I think you're falling into the same trap of believing other economic actors will happily agree to your proposed "solutions".
Disadvantages of NFC payments:
1) economic friction which lowers supply of drivers: drivers have to buy $50 NFC terminal from Square. $50 is not a lot of but it's extra financial friction which deters potential drivers
2) trust issues which lowers supply of paying customers: NFC payments puts the payment amount in control of the driver which makes potential customers fear getting scammed. In the Uber/Lyft model, this doesn't happen which is a significant psychological advantage because drivers are notorious for playing games with payment (especially with foreigners and travelers). By letting the "service in the cloud" pay the drivers on behalf of the passengers, it adds accountability.
I'm not claiming it's impossible to create a car-on-demand service that uses NFC and/or credit-card swipes. I'm saying it would be a disadvantage to other platforms that work more conveniently. This means less paying customers which leads to less capital to continuously improve the software -- which could then lead to more customers abandoning the co-op rideshare app for the more polished Uber/Lyft apps.
Again, see the failed non-profit RideAustin losing riders as somewhat analogous case study. And see the other comment about the apparent low quality of this thread's app (Drivers.coop): https://news.ycombinator.com/item?id=26592354
The co-op needs capital to improve the app software and you need a virtuous cycle of paying customers that don't avoid (or abandon) the platform to provide that ongoing capital.
>co-op would not have to make riders create accounts and associate payment information with them. That removes some complexity for the user,
This wouldn't be an advantage for commuters that use Uber/Lyft daily.