The other thing the government (specifically, Graeme Samuel, Rod Sims and the Australian Competition and Consumer Commission) did was structure the NBN so that small operators couldn't join without buying connectivity from one of the large incumbent players.

The original model for the NBN was that there would be 14 points of interconnection nationally, which means if you were a smallish ISP you only need a physical presence in 14 locations to be able to offer service on the NBN nationally. That was the clear preference of NBNco itself, and the smaller (often regional) ISPs who now had a real shot at becoming national operators and challenging large incumbents like Telstra, Optus and TPG.

The ACCC decided that it does not, in fact, want to foster or support competition and that it wanted to continue the status quo, where a handful of large telcos control the market. NBN instead ended up with 121 POIs, which only the best capitalised carriers could service. That lead to massive consolidation in the market; many small to mid sized players either closed up shop or sold out to operations like TPG, and the small operators who survived now buy wholesale connectivity from the incumbents.