This analysis is solely focused on the "job" aspects of pre-industrial life and includes almost none of the domestic considerations. I'm not sure if it would be fair to call all non-wage time "leisure". Once work was still over there were still things to clean, fix, prepare, butcher, etc.
Although, I think it goes without saying that before affordable lighting and heating, we all underestimate how lazy winters were for the average peasant, whether idyllic or not (accounts I have read make it sound incredibly, incessantly dull).
And I think the best evidence we have that we are overrating the quality of pre-industrial leisure time is that people developed almost no leisure activities! Common people had almost no sports, no games (beyond precursors to Bocce or backgammon), no literature! They supposedly had half a year of doing nothing, and perhaps singing and drinking was sufficient to fill the time, but you'd think they would show lots of other innovations. Or even steal the activities of the rich (organized sports)!
Instead you don't see leisure activities develop until the rise of the 40 hour workweek and the availability of consumer appliances.
Edit: I hope people understand that the argument the article presents is largely a romanticization of poverty.