Large farming estates are still run by the modern gentry to a certain extent, however they often choose to delegate these sites typically to the highest bidder who pays the estate owner the right to manage the land in exchange for living and working there.

With the costs of modern machinery and the technical know how required to use said machines coupled with modern scientific practices used today, it's the sort of career that only well off savvy individuals can survive in. The modern farmer has to have a firm understanding of Agri-economics, mechanics, chemistry, animal husbandry and many more skills in order to compete in the developed world all of which requires a pretty decent economic up-bringing these days.

That isn't to say that poor tenants don't still exist today but more often as a result of falling on hard times then class origins.