Cutting to the chase... nothing but attitude.
The expense of developing martian real estate is so high (and letting others do it so abhorrent to the control freaks) that the elites have decided nobody should be allowed to do it without their control.
Mars has 14.4 billion hectares of real estate. Musk, in late September, will announce his plan to send people to mars. Nobody owns mars which stifles its development. But a simple attitude change could open the flood gates.
Suppose we set up a trust for one single purpose. We auction off hectares starting at the proposed first human landing site. All that money goes into the trust. From that trust we only buy transportation tickets, payable on delivery of a live human to the surface of mars near enough to connect with an established colony.
This is a win-win-win-win.
win#1. The transportation company sells tickets at a profit competing with others for the lowest possible price.
win#2. The land speculator sees the value of their property appreciate as more colonists arrive.
win#3. Colonists already on mars have a ready made market for their time and materials to be sold to new comers.
win#4. New comers arrive wealthy by virtue of whatever mass allotment for personal property is included in their transportation ticket.
Before new comers leave earth they can contract with existing colonists for eventual trade when they arrive. 100 kg of disposable personal property would be worth its transportation cost alone.
Cost/kg per lander = ($200m / 2000 kg.) or $100k per kg.
Lander ($100k/kg) x 100 kg, so each colonist arrives a millionaire with a mansion waiting for their arrival and enough resources to follow any individual dream.
It's just attitude that holds us back.
Update: Jim asks, "Who do you envision auctioning off Mars? Who do you envision bidding?"
This is the fundamental problem. Who gets the loot? If not 'me' (whomever me might be) we're just not interested. The trust auctions off mars with all of humanity being the beneficiary. The trust doesn't belong to anyone. It's sole purpose is to buy tickets to mars (or anyplace else a similar trust is set up for using its real estate... but we start with mars.) Who bids? Any person on earth wishing to speculate on the future value of martian real estate. I would also propose the plots to be 40x50 meters for a minimum bid of $1. This provides a minimum of $60b (but in reality much more) at 84% utilization (all property having a minimum frontage of 40 meters on a planetwide road system.) Only individuals could bid on these plots which could then be resold and aggregated in a secondary market. It just requires govt. to acknowledge titles.
I would also recommend (but it's outside the focus of this post)... All governance would be local. A township would be 10x10 km. with each square kilometer choosing a resident as its representative. All laws would sunset after one martian year from the moment of enactment.
It is idiotic to look at it from the perspective of, "I wouldn't pay a dime for a 2000 sq. m. plot of real estate on mars." The only valid perspective is "would others?" Given the govt. support of the validity of title the answer doesn't require an active brain cell because even without it humans have been willing to make similar investments.