Multilateration still requires precisly surveyed sites and I would believe a lot more stations to get coverage where an ADS-B groundstation with ADS-B equipped aircraft may only require one sited at a major regional airport in leu of the promised radar sites. To get coverage within the J curve I would be very very surprised if costs less than the equivalent in ADS-B stations. Total coverage would be way north of $100mill.
Do you honestly believe that over a billion dollars has been saved by shutting down the FSUs? No creative accounting allowed. Cost of staff and upkeep of facilities please! No adding values of infrastructure or real estate or charging of commercial rents and dividends to the shareholder allowed.
As for getting realtime wx for your nav system. I have been trying out a program on my GPS equipped PDA/Phone "POCKETFMS" I can download realtime radar from BOM that has aged no older than 15minutes and METAR?TAF whenever I am in 3G coverage from the ground and air. Seems to work OK so far.
We have no chance of getting satellite . However,as qouted a long while ago on this site, 3G network is expanding all the time. Maybe we will have to consider a use of that network for data uplink. Cost of a dedicated geostationary satellite purely for aviation use( even the yanks couldn't prove this case as economical for their uses and piggybacked on satellite radio network) vs a broadband connection from a 3G simcard