Rent it out to strangers, let friends live there for free if you want. Do anything other than letting a home sit vacant when there are tons of unhoused people sleeping in the street.
All resources are scarce including life saving medical tech. Do you force redistribution on all resources and assets?
You obviously don't seize obscure collectibles because there's limited public interest in such a collection. But that too has limits at the "logical absurdity" extreme: you might seize a historical artifact or painting from a private collector because it was looted from a museum 90 years ago before re-entering the private market after a few decades.
And, yeah, you might seize an abandoned property to prevent the community it's in from decaying.
I feel that if you can show something is abandoned, it can be up for grabs, including my personal property.
Now to define "abandoned."
In my home town, a potentially lucrative piece of real estate was fenced and not maintained because the owner was pissed at the city. The only reason they held it was because "fuck you city." I could see an argument as saying that it is abandoned and should be forced to be used. I can also see that as free speech because the owner was making a statement about local ordinances. Is it abandoned or an active political statement?
Aside from the obvious goal of keeping out trespassers, I'd be willing to bet the fence was added based on legal advice. In a few years there will probably need to be some further "improvement". Perhaps as simple as replacing the fence.
We're going to do that on a case by case basis depending on reasonable things like the user's need for it, other people's need for it, what the neighbours think of it etc.
With courts and whatnot.
And there's nothing you can do about it.
Kind of reminds me if the old joke:
A guy asks a gal if she'll sleep with him for $10M. She, says yes. He asks what about for $100 and she is offended: "what kind of woman do you think I am!?" To which he replies, "we've already determined that, now we are just haggling over the price."
"Your home has to have people in it" is, 100%, a valid policy goal. And in extremis, paradigms like adverse possession exist to ensure this.
Yes, people need and should be housed. No, that doesn't mean they need _my_ house. Build up public housing resources. If the govt wants to buy my property at market rate and give it away, and I agree to sell, go for it.
Otherwise, I hear you have a good retirement fund that you spent years building. I didn't didn't do that, so just give me half of what you saved and we will call it fair.