I agree this vision (as stated) is fantasy, but I've often speculated about whether it would be smart to buy up land that was formerly used as landfill. It doesn't generally seem to be considered valuable.

I suppose this is because it is not desirable for property development or agriculture... the killer might be assuming some liability for environmentals but I never investigated that in detail.

An interesting option would be to try and buy just the mineral rights. The seller will probably think you're crazy, and they might be right.

In any case, a landfill operation is close to the reverse of mining, and while the extraction technology one would need isn't here yet, it's hard to think of how you could get greater concentrations of natural resources all in one place. Plus everything is at least close to the surface.

Another major downside I can see is that landfills tend to be too close to built-up areas. People want their trash to go "away", but also they don't want to take it too far. Which then leads to the surprising mental image of landfill "ore" being dug up and transported to a remote processing site.

[this is why I think the author's vision is mostly fiction -- it's hard for most people to imagine the sheer scale that modern resource extraction operations need to be profitable].

The slightly unfortunate part is the "crazy grandpa" image that leaving such a legacy to your descendants creates...