If the “firm belief” is that people will require very high speed internet connections to get a fair go in life – not the same thing as faster access to cat videos – then the question becomes how much are you willing to spend, per head, to give everyone that go?
If satellite is never going to provide truly high speed - low ping - connections, then an awful lot of money will need to be spent on between 3% and (guess) 9% of the population; far more per household than city dwellers.
One of the problems being – because of the likely project duration – each election there is a saving to be made by scrapping such a (nation building) project, or continually scaling it back (as happened last election, to an extent, with FTTH).
Like the telegraph, railways and a great many other Victorian era mega projects; they were done almost as much to display the might of the builder – for the love of doing the project – as they were to provide useful services. The point also has to be made that labour costs and conditions were somewhat lacking, compared to today.
So whether old (or not so old, as with microwave) facilities are upgraded and utilised for 21st century comms isn't really the issue (either that is cheaper/better than an alternative, or it isn't) but whether successive governments want to stump up several billion – never mind a single billion to get it started - to connect 100% of the population, in a speed-time equivalent way.
There will almost certainly never be a commercial reason to hook up the 3% - and probably the same for many of the 6% who live nearer civilisation, but not quite near enough – so either it's public money, or it's the best we could manage (sorry).
Long term investment – chasing a dream because you should – is a difficult business. There are many ghost towns, in a very vague line between Adelaide and Alice Springs (and in many other places across the country) that were built for what once must have seemed a great idea - and may well, short term, have been just that - and/or through a lack of “foresight”. It will never be the future and in the future, people will very probably look back and marvel at how enterprising and industrious their forbears were (and had to be), when compared to themselves.