Landlords generally spend much less than 5% of their yearly rent income on maintenance. If they actually do something to improve an apartment, that is just an investment in their own real estate, that they own 100% even after having other people pay for it several times over during decades.
Edit: Or look at it this way: Would you hire and pay somebody a good salary for working maybe 5 or 10 days per year for you?
You might be surprised to learn that many small rental properties are heavily mortgaged. Along with insurance and property taxes, the biggest cost is usually mortgage interest. Some owners even lose money for a few years until the rents rise to meet the costs so that they can break even. (These owners are playing the long game, believing that rent and property values will go up over time and eventually their investment will be a good one compared to their other investment options.)
> the biggest cost is usually mortgage interest.
The tenant is paying for that.
The situation is absurd. The tenant is paying the entire mortgage and interest for the property and can be kicked out at any time, while the landlord does basically nothing, pays nothing, and the bank can not kick him out just because they please.
Increasing risk will eliminate a lot of the "mom and pop" landlords (widows, former small-business owners, retirees, etc.). If it is too risky to own only a few extra condo units or a single small apartment building, then those properties will go to large corporate landlords.
> there are people whose sole contribution to society is "owning flats".
Landlords make sure the utilities (water, electricity, heat, etc.) work, that the roof doesn't leak, fix plumbing issues when they arise, take care of pest infestations, etc. Even landlords who don't personally fix things are employing managers and tradespeople. And with big corporate owners, the shareholders are usually pension funds which effectively are the retirement savings of people who have already "contributed to society".