At least in North America (and the author seems to be from Canada), having a company give you any sabbatical at all is pretty rare, and 6+ months is pure fantasy:) And not everyone likes travel, the post actually explains his reasoning pretty well.
I've seen this before. Had a vendor become helpless after their only engineer took a 6 month sabbatical. Had to cancel orders and switch vendors because they stated "Until the engineer returns, we can not quote a delivery time." Imagine being that company...
This stuff can be negotiable if asked for and planned correctly. It won't be offered.
The Danes do it best, they basically shut down the country for 3 months every summer and have an unspoken agreement that nothing will get done.
Is there a skeleton crew to run grocery and fuel?