City transport is directly affected by what's happening outside the city. Less road traffic, more space by the ground area saved by gradually building a monorail network. Such a project could be started in the most heavily congested areas thence spread in a spider web fashion to the suburbs & beyond. Many other services such as power, water & communication could be incorporated in a Monorail design. Ease of access for maintenance, no flooding, no inaccessible tunnels & subways. Imagine the cost savings there in the long run ?
It just requires a handful of thinkers to think past their bank accounts for a while.

As a retired train driver heavily involved with the electrification of the Perth Metro system, I do believe I have some first hand knowledge of what needs to be done to improve our public transport systems.
Firstly, we must recognise the FACT, that our States receive massive amounts of money from owners of every automobile on the roads today. Even if they just stay parked in their garages, they still provide massive amounts of funding to the state via Stamp Duty, G.S.T. Excise on fuel, taxes on certain vehicles considered luxury vehicles, and taxes plus GST on every part you buy for your car or cars. To the State Governments our cars are a gold mine that just keeps on giving.
Therefore for anyone to even consider a proper public transport system we must also give thought to replacing that income source if they sell their vehicles and go for public transport. Then we also need to consider from where will states source income that is lost in this manner ? We're already facing this with the influx of electric vehicles and still no reasonable solution has been found.
When the above has been resolved, only then can we again approach the issue of public transport honestly.
One thing is for certain, states cannot keep increasing the charges to the public to travel on these systems. Further, given the cost of installing and maintaining systems for fare paying and also considering the majority of public systems are subsidised by the taxpayer to a large degree the funds released from the fare paying systems by allowing ALL TRAVEL ON PUBLIC SYSTEMS TO BE FREE, would go a long way to be equitable.

Itchy,
You are making a very valid point. My view is that a Monorail network could be a solution to many problems plaguing our transport system. It would be environmentally good, it would alleviate road traffic congestion, it'd would make delivery of other services such as water & fuel etc cheaper & easier because all these could be incorporated in the one system, no need for bridges or tunnels, no road crossings, freeing up area for car parks in cities, the list goes on.
As far as cost goes, a Monorail system would cost no more than traditional rail systems & could be future-proofed from day 1.
Imagine going to work on a Monorail & viewing the scenery in comparison to being cooped up in underground coffins on wheels.