Except that like everywhere else on the globe that isn't Antarctica there were already people there that needed to be displaced. Someone else's asset was stolen and sold (for very little initially, but sold nonetheless). Land (in absolute terms) has little to do with property prices compared to where the land is geographically, politically and socially.

Land tax will help marginally with inequity but the majority of the cost will just be passed on to renters (like what happens now). Taxing vacant buildings higher will increase supply which should depress rents slightly. None of that stops housing becoming an investment and a financial asset though which is the root cause of unaffordability.