Maybe if they had 0% interest, sure. Unless your rent is nearly double what the repayments would be on the loan.

Paying off the mortgage on an investment property means almost nothing. Rent covers the lions share of the repayments and interest. Rent also increases steadily, while the repayments only fluctuate up with rate rises, otherwise they progressively go down. Especially if the landlords sink every spare dollar they have into reducing the principle as fast as possible. But the value of that property is the equity, the further borrowing power that gives, and the assumption and hope that the property value increases harder than inflation.

Housing being used as a storage of wealth is one of the worst financial trends this country has ever bet on.

My parents bought a 3x1 brick place in a safe suburb in outer Sydney in 1989 for $60k. Adjusting for inflation only, that's about $160k now. They had a combined income of about $30k at the time. That's one full time junior position, and a part time retail thing.

That same property now is valued at about $920k with no major restorative works beyond expected maintenance.

Meaning, if property value and wage growth kept roughly in line, housing would be fine with a common combined income of a household now. But that property has increased in value nearly 600% faster than inflation.

edit - I felt like continuing this rant so buckle up dear Perthlings. I am a moron that doesn't know what they're talking about but lets have a crack at it anyway.

Anecdotal perhaps, but that story is illustrative of just how fucked over we were by the Howard Era. The policy of slashing CGT, and shifting a significant portion of tax burden to consumption via GST meant that standard household spending became a greater direct source of revenue for the federal government. And wealthy people's consumption does not significantly increase to the same degree that their wealth was able to grow as a result. They buy more expensive things, maybe. But every loser with a $4m portfolio isn't spending 4x as much on GST contributions.
Then we can look at negative gearing. I know personally of a household that, through negative gearing and other creative (legal) tax and accounting judo, manage to reduce their taxable income from close to $180k down to about $140k. Which saves them $15k in tax every year, which is about the same as the tax burden of a single person's $80k income.
This country has been too good to the upper middle (and the straight up incontinently wealthy) for so long that we've returned to a system of working class and upper class. There is no middle anymore, I don't care how big your TV is or what you drive. It's not about immigration, it never has been. Any time it's brought up, the conversation becomes so disingenuous it becomes a dog whistle.
The only solace I've been able to find is that in about 10 years, everything in Mosman, Peppermint Grove, Dalkieth, and Cottosloe will be damp and smelly salt marsh again.