As a recent FTB'er we took out a large mortgage, because frankly that's the only way you could buy a property. It's within the realms of what the bank deem as affordable, and i've got at least another 35-40 years of potentially working, so in reality it's quite insignificant.
A huge drop in the house price as a result of taxing property wealth instead would plunge us into negative equity. Should the government cover that shortfall? You claim if it's to be for the greater good then so be it. But you'll have hundreds of thousands of FTB'ers who have purchased a property in at least the last 5 years who will now find their property worth significantly less than the balance they owe on it.
That's not for the greater good, that's just having a narrative to suit you because you've not been able to get on the housing ladder. The "i'm alright Jack" attitude works both ways.
Nobody is entitled to risk-free asset appreciation. If you would benefit from price increases (which owners do), then it's only fair that they should also suffer from price crashes. That's what an investment is.
Buying assets on leverage is risky. You're gambling and sometimes it doesn't pay off. Why should the government bail you out? Homeowners usually feel entitled to privatise the gains and socialise the losses.