One mitigating feature of KoL is that it limits how much you can play in a day. You get a base of 40 'adventures' each day; you can add to that with things like the Girls of Loathing Wall Calendar and by eating and drinking (it's the only game I know where people value cooking skills as highly as combat, and where you can get Liver of Steel as a quest reward) but once you're full that's it. It can still take a fair bit of time, but at least it's limited.