I can see drivers/passengers travelling together for weeks or months at a time. So you'd probably just want to quit Lyft and enter a private arrangement. Is there anything in Lyft's business model to prevent or mitigate this?
"Service Fee. In exchange for providing the Carpool Platform, Clara Rides may assess a service fee on each Carpool Ride (on either or both of the Carpool Rider or Carpool Driver). The amount of the applicable service fee shall be communicated to you in writing."