Because he has unrealized capital gains - in yearly income/expenditure their losing money but big picture, when they sell, they profit.
In Australia, rental returns are paltry (less than 2%) compared to any other investment, but steep tax concessions on and insane capital growth (often higher than 6% annually) incentivises speculative investment in real estate… This is what’s driving up the cost of housing to the cartoonist levels they currently are in. It’s not unusual for these speculators to not even bother with tenants, because like op suggests they often lose money maintaining the property, it’s cheaper to speculate and maybe renovate immediately before selling.
The problem has nothing to do with landlords and everything to do with speculators going for capital gains. Greedy landlords can be a problem where there are no rentals protections, but that can easily be resolved with regulation.