This is exactly what happens in Milan and in the whole Lombardy region! I have a 2014 Euro 3 and it won't be allowed to enter in Milan (Area B) starting October 2028 but I really don't care because it will be 14 years old and once it will be 20 years old I will apply for the historical registration (CRS) and use it with no limits until its natural end. Outside Milan resctrictions will apply mostly on winter months so it's not a real problem.
I thought a lot about it and I have no plans to trash money to update to Euro 4, Euro 5, Euro 6.... They want you to spend a lot of money trading in the old bike to only get 3 new years of "allowed use" each time you step up the Euro number. I'm having my tubes removed and my wheels sealed and next I'm going to update my suspensions to full Ohlins. In the future I could consider the idea to add another bike next to nineT but it should be a totally different bike with better performance, not the same bike with less performance because of the new regulations.
In the end, over here, we'll be allowed to drive only electric bikes or historical bikes.