Lyft deactivates their drivers for low star ratings. Don't let Lyft make you think otherwise. If you score lower than 4.80 and receive some questionable feedback, you are toast at Lyft.
If a former Lyft driver presses on the driver mode button in the Lyft app, they will see the image above. Basically, the system detects this former driver and sends out an error message.
Lyft won't contact a former driver to drive on their ridesharing platform again. They use their drivers, and then dispose of those who score less than stellar scores that would be good and/or above average at competing ridesharing companies.
In any case, the image above is what a former Lyft driver can expect if they click on driver mode.