There seems to be some conflation of communication protocol and security protocol, which are two entirely separate protocols. The communication protocol, i.e. 802.11.x, is what provides the band with, whereas the security protocol, i.e..WPAx, provides the initial connection protocol and the message encryption; these are mix and match. No one is suggesting that Tesla should support only WPA3, any device can support multiple security protocols and multiple communication protocols, and virtually every wireless device that I have used does. But it is in Tesla‘s best interest to support WPA3 because it is a vastly superior security protocol.
I have configured my main network to be WPA3, but I have my guest network configured with WPA2 and connect my Tesla to that network; guest networks generally have isolation from the main network so that allowing WPA2 connections to my guest network does not jeopardize my main network.