When you consider, rather than pay for the 600 ground stations required to give proper coverage over our land mass, (as the FAA has done) Airservices have just put in a handful
The following map would indicate about 60 ground stations.
http://http://www.airservicesaustralia.com/wp-content/uploads/adsb_at_30000ft_GM.jpg
I'd be the first to say that coverage should be a minimum of 10,000ft, more units, better redundancy if one unit fails. But, and its a big BUT, User pays, so if Industry wants more ground stations then this could be supplied but User pays.