I have seen the light! Thinking about what I said yesterday I have realised why TPG have acted the way they have, and that they are not quite as stupid as I have tried to make them out to be.
TPG are totally focussed on "churn"! Of course "remote activation" is possible in premises where there is already a working NBN connection, but the previous tenants have left taking their ISP modem with them, and the NBN box has been commanded to go quiet because no-one is paying ISP fees.
The failing of TPG in all the above was that no-one had the clarity of understanding to say "You require a new NBN connection, but our Setup Guide only describes the actions appropriate for a new TPG customer at premises which already have an NBN connection".
So my request for better information to customers includes that it be made clear that my suggestions above only apply where a new NBN connection is required, that things go rather differently where a new NBN connection is or is not required, along with enough information that new customers can recognise the difference.