Previously, a government could monitor what site a user is visiting just by looking at the TLS session startup. Even if it is hosted on a cloud provider and 100 different sites are hosted from the same IP, they could look at the TLS-SNI data in the plain text to choose to interrupt and block the connection.
A fallback would be to manipulate DNS queries and force all DNS queries to be directed to official DNS resolvers. But DoH makes that far harder to control.
This is a bluff being called. Tech said "If we make it so that they have to spend all this money and build a massive scale intercept that actively participates in each TLS session, they won't buy into the cost."
Costs keep going down for this sort of thing. Now there are large organizations and governments willing to work on this stuff.