As I learned this summer in Italy with my intermediate language skills, "commercial" truffle hunters purchase tree saplings whose roots are pre-seeded with truffle fungal spores, then plant them on terrain with the qualities (sun facing, slope, stone content, etc.) that make favorable growing conditions. As the trees mature, you start getting regular annual harvest of truffles, but you will wait years before you have anything resembling profitable truffle production.
Once your "habitat" is stable, though, you can continually generate truffles during truffle season for more or less generations, assuming the climate doesn't turn on you. You'll need animal support, of course, to harvest :)
Climate change is currently making annual volumes volatile, as recent seasons have seen too much water or not enough. In addition to defending their own private lands from trespassing thieves (who regularly try to poison their truffle dogs), commercial hunters have had to learn new skills at water management to keep their grounds in as "stable" state as possible during truffle season.
Of course, when you have a bunch of land with trees growing on it, it's normal to also grow food and livestock, too. It's very to _only_ deal in truffles for one's livelihood.
What usually happens here in Italy is that someone comes out (it is at least 30-40 years that this thing comes up regularly) with a new, better method to "insert" truffle spores in tree saplings and is wishing to sell you (for a dear price) these trees.
Only, for some reasons in your particular patch of land (which is regularly "approved" after having made - BTW expensive - surveys and laboratory checks/analysis on the soil) this doesn't happen (after 5 years, and they tell you that is too early) then nothing happens after ten or fifteen years and by that time you can't find the seller anymore or even if you can they will tell you that yours is one of the rare cases where it didn't work.
Anecdata of course and I sincerely hope that some other people had more success, but from my experience in the local agricultural district I know rather well, people that report success are maybe 5% (and likely they are IMHO lying).
Besides - at least here - land is usually raided by wild boars that - like pigs - are very capable at finding truffles.
I don't doubt that it can work, what I am telling you is that AFAIK it is not a "surely working" approach, if you have some land and some spare thousands Euro to invest in an experiment, it is fine, if you think that those thousands Euro will surely grow to a few tens in fifteen years, you are most probably wrong.
Ruff ruff! Beautiful documentary about that: https://www.youtube.com/watch?v=KFYhrc0AnVw
[0] https://www.smithsonianmag.com/innovation/american-grown-tru...
There's probably bacteria involved, as well - some fungi species seem to exploit super specific niches, with super specific environmental conditions needed to spread and fruit.