It's not like ISPs could have build and extended their bandwidth over the last years, for example with the 40 €/month my father pays for < 16 MBit internet connection.
After the pandemic, we can discuss the whys, and ,make sure it doesn't happen in the future.
While the infrastructure is quite stable where it has been extended, those rural areas ("not prioritized for broadband builds") are also affected by the lockdown, people have to work from home, use the internet all day etc. pp. In those places, the infrastructure reaches its limits pretty quickly all the time. This will cause _serious_ damage to local businesses for no good reason other than ISPs unwillingness to invest there.
edit:misspelling