Because they needed to understand the signalling there and safety systems implement it in the game and then get a license from a train company in Italy to use their logo and train in the game. If they can't get the licence then they can't make the route
They also need: 1. To be convinced it will make a profitable return on the investment in research and development. 2. Worth sending someone to the area for research or having a professional and reliable local partner who can do so. That includes being able to talk with authority to the relevant railway organisations (infrastructure and train operator), able to obtain sounds and assess physics performance of the various trains. Although Covid seems to be receding (largely replaced by the other current major world event... ) it still poses a challenge to getting out and about to do research, particularly where foreign travel may be required.
They need to research for this and best way to introduce Italy might be Brenner Bahn Innsbruck Fortezza South Tirol. Because there's PZB ETCS Sifa 15kv 16.7hz AC Brenner Innsbruck ÖBB Infra pretty much the same equipment as a German route. New Stuff is 3kv DC 1.45m copper contact strip also suited for French and swiss 15 & 25kv AC wires SCMT RS4 Brenner Fortezza. ÖBB1216s and 1293s can run all German routes including Brenner Bahn while E412 can run following German routes HRR RRO Ruhr-Sieg Nord Schnellfahrstrecke Köln-Aachen Main Spessart Bahn Aschaffenburg-Gemünden and Hauptstrecke München-Augsburg. The reason why it cannot do Nahverkehr Dresden and Tharandter Rampe Dresden Chemnitz (Karl Marx Stadt) is that E412 lacks 25kv 50hz & 3kv DC 1.95m Metalized carbon Pantagraph Mirel Southern parts of former Czechoslovakia.
Not just trains and signals. They would need lineside assets, houses, shops, factories etc. No point using UK or US buildings which would look out of place Then you have people, and yes trains, signals even the ballast and so on. It's not just "Make an Italian map", there's a whole ecosystem that needs to be built and if it's only used once it only gets paid for once. If they can reuse it (ie enough people would pay for more routes from the same region) then they can get paid multiple times for using the same or similar system
