With my Garmin standalone you could specify areas to make it fit your capacity. IIRC it was not just a choice of dropping back from 'all Europe' to UK and Ireland only. I think you could selectively exclude outlying areas such as those parts of Russia, Turkey etc sometimes included on European mapping.
If full coverage now exceeds the capacity of some units I dont see why Garmin cannot give a choice of Europe update versions with slightly reduced coverage to fit under 8GB. I think they already limit the area of updates based on the price you pay. eg UK and Ireland only , Western Europe only, All Europe, etc. Why not add an all Europe sub 8gb version? . (Or versions- You chose which are coverage best suits your needs. ) Its bad enough that they might render a standalone obsolete in this way, but they shouldnt be able to do it on a unit fitted to your car, if you willing to pay for updates.
I believe the Garmin Explore web site lets you manage way points and routes etc on some GPS trackers. But as far as I know it cant be used to download the map updates to your computer , delete map files for countries you dont need and then upload a smaller update to the car. Unless someone knows different
. Possibly a security risk to their paid for updates