I think a sub-$30K sedan will be quite successful, if it can carry 4+ people, 350+ range etc.
What indicates such a product is coming from Tesla? The robotaxi is only 2 door. Unless you mean continued price cuts to the 3, which seems… ambitious.
Unless they are planning a 2-bench version of the cyber taxi, same basic chassis and internals but a conventional passenger car, then yes, probably their next move has to be discounts to Model 3. Would require some significant cost savings even beyond the giga press and other strategies being employed. Maybe make it in Monterey...