[noisy_boy]

It should be much more punishing from the 4th home like 45%. One can understand 2/3 homes, e.g., one to live in and the rest as investment for retirement income. More than that is just greed. Also, if you don't live in one of your properties, either sell one to keep the total number within 3 or pay additional tax.

[immibis]

if you allow each person to have 1-2 investment homes then you have the exact same problem but now it's decentralised and more people (more voters) benefit from the problem continuing to worsen

[noisy_boy]

I mean that can be adjusted/tightened - you can say one to live in and one for rental and that's it. Other factors like other investment income etc can also be part of the criteria.