They say it because they are trying to get rid of us. It is not true, we update firmwares via USB, it is only that some firmwares leaked to forums, FCA does not share these to customers (via say my alfaromeo account or any other my maps), and they are normally not willing to give anybody update as it takes their time, and updating from earlier versions than MV072.xxx.xxx requires then to update 6 other ECUs (officially, unofficially they work OK without update). Updates is hassle, takes time (IPC is like 1h, used to be 4 two years ago but they optimized Witech2, other are much faster) and brings some risks e.g. of bricking (I heard from my friend in one dealership of two IPC bricked during update).
Surelly FCA is not willing to do anything. Probably telling them that we do update ETM firmwares via USB ourselves and what they say is bulls..t won't help at all - they will say it is not official and without required other ECU updates not safe or so.
Alternative option is that wide screen sits somewhere in Proxi, but we do not know where - of course they won't tell us, surelly they will again say modifications of proxi is not safe etc.
Not sure if you are planning to keep pressing on them, or give up?
Anyway, thanks for your attempt as far, looks like my next phone will be iPhone + will add WiFi Carplay bridge.