Alternatively, the aperture of the antenna on the satellite can be increased. So high-gain from space, but low gain on Earth, which is the approach of AST SpaceMobile.
IIRC SpaceMobile showed direct-to-cell satellite communication recently with 5g. Still to be seen if they or someone else (SpaceX?) can make it work large scale.
SpaceX has been launching direct-to-cell satellites for a bit now (a couple per Starlink batch), IIRC they said they need to get to ~300 such satellites to provide consistent service in at least some places. Although, again, worth emphasizing that 'large scale' in this case is still just to provide emergency coverage in places with no other coverage.