I doubt people who couldn't stick to Duolingo would have stuck to the boring advice HNers have like reading grammar books and watching in-depth Youtube videos that require much more attention.
It seems that people just like ... different things. Some people actually look forward to curling up with a hot, meaty grammar book, for hours on end. And find that both apps and videos (unless done very, very well) just drain their batteries.
It seems that people just like ... different things. Some people actually look forward to curling up with a hot, meaty grammar book, for hours on end. And find that both apps and videos (unless done very, very well) just drain their batteries.