I've been doing 60 minute boils with the lid mostly on the pot for about 10 years and never noticed DMS. Well, either you're lucky or have a high threshold for DMS.
Could be lucky, but I expect that it is modern malts and/or I have enough water vapor escape to drive it off. A couple of months ago I took a Dortmunder to my homebrew club to specifically test for DMS, only one person thought they tasted DMS, but only after it warmed up. I have to say for a while I wondered if my wife and I couldn't taste DMS.
I originally started with the lid mostly on, because I once had a bird poop on a porterhouse steak I was taking to the grill and I didn't want any stuff falling into my beer. At the time I didn't notice any quality loss in my beers and I noticed that I saved propane. Maybe I should try a more scientific experiment for myself, one pilsner beer with the lid off and another with my normal process to see if it matters.