The swamps were dried up as a state initiative and replaced with what is now one of the largest artificial forests of Europe, if my memory is correct for both sanitary reasons and to produce trees for shipbuilding.
> In the 19th century, as the marshes of Landres dried up and the shepherd’s need to move on stilts began to disappear, the practice became strangely fashionable among some of the more eccentric aristocrats of French society. In the early 20th century, stilt marathons were held in Paris, celebrating the French agricultural tradition.
As you say, this was an intentional afforestation project which ended pastoralism in the area; it's not merely that the shepherds' needs changed as that there were no longer shepherds. Aristocrats finding amusement mimicking the practices of a group that was effectively destroyed by a national action seems at best lacking awareness.
https://en.wikipedia.org/wiki/Landes_forest#History https://en.wikipedia.org/wiki/19_June_1857_law
The forestation project improved longevity and allowed the area to build other sectors and to integrate with the wider economy and society. I'm sure if you reforest the Sahara some will lose their livelihoods but it also would have many benefits for many people.
https://www.swsurfhouse.com/blog/history-of-landes
https://www.green-resort.com/en/experiences-us/nature-discov...