It would be possible to cobble together a somewhat inelegant solution for US residents travelling overseas. There are quite a few apps such as Airalo (
https://www.airalo.com/ and on the App store here -
https://apps.apple.com/us/app/airalo-esim-phone-internet/id1475911720) offering eSIMs to give world wide data connectivity. The data isn't particularly cheap but for relatively short trips possibly a solution on its own as long as you only make voice connections via FaceTime, WhatsApp or anything else that goes over data and you don't need to be able to receive SMS messages on your international number because as a data-only eSIM there won't be a number to send messages to anyway. But even that could be got around by also signing up to a rolling (monthly) VOIP number in the country you are visiting and running the VOIP client on your phone (I did say it was somewhat inelegant!).
Even if this move in the US is a wakeup call for carriers around the world 12 months is a long time for US travellers to have this problem. If Apple did care about that market I wonder whether it could create some sort of unified service where it offered a data eSIM similar to Airalo coupled with a virtual VOIP number in a decent number of countries around the world and all integrated together such that when overseas a traveller could have calls to their overseas VOIP number forwarded as an incoming FaceTime audio call and SMS texts forwarded to iMessage. I guess that if Apple was going to do that it would have done so already.
In my view that would have been a decent thing to do to ease the pain of US travellers and in the mean time be an extra revenue stream for Apple since the data and VOIP number would cost money. Some travellers might even prefer that as a long term solution since if it could all be set up online for any country you are about to visit before departure and you are instantly allocated a virtual number in that country and you don't need to install and VOIP client software because it all integrates seamlessly with FaceTime and Messages.