A newly deployed satellite with narrow spot beams could surely have capacity for the entire country. Transponders are able to be re-used this way. Similar to how NBN Sky Muster works with a mix of narrow spot and wide spot beams.
For example the existing national beam could cover ABC/SBS. Smaller but still wide spot beams would cover commercial multi-channels and also local market channels in outback SA, WA, NT and QLD and then use narrow spot beams to provide the local market channels in the higher populated areas. ie. VIC, NSW, TAS, SA, Coastal QLD.