Other than the risk of being evicted from your rental, a homeowner has most of the risks of a tenant, plus more. And there are a fair number of protections for renters to lower that risk. There are some risks of the landlord being a bad player, which makes the renter's life worse.
The landlord has the risks that the renter doesn't (that a homeowner does); which is risk offloaded from the renter to the landlord. The landlord then has the risks of the tenant being a bad player, which can be extremely financially risky (worse than being fired from your job).
> from my POV, seems like a low risk investment to be a landlord
Your point of view is extremely far from the truth. Especially for landlords that have one or a few places they rent out, it can be extremely risky. Everything from tenants just deciding not to pay (and taking a year+ to evict) to a Pacific Heights situation, where the place is destroyed with no real recourse. Or, on the lower end, tenants just leaving the place in bad shape, with bugs/mice/whatever; that itself can cost tends of thousands of dollars to recover from.