But, yes, I used a hyperbole, it is a classic tool of rhetoric. I could have said that they just learn how to ask for a coffee, or the directions for the Eiffel Tower. The meaning is the same.
Can a person find a way to waste hundred hours on Duolingo? Sure. I got perilously close :). But after a tenth of that I could generate sentences for friendly emails and at beginning meetings etc when I actually tried to learn.
Has the "100 hrs and not gotten beyond hola" been your personal experience or somebody you know? Trying to understand if I'm arguing with a strawman / straw scenario, or actual occurrence. If latter I'd be genuinely extremely curious to hear a lot more! What were the 100hrs spent on?
But among the people (about 20) who have told me they have used Duolingo to (try to) learn my native language, I have yet to find one who can say more than a few disconnected words. And among the people I have seen who are fluent in my native language or the other languages I speak, I have yet to find anyone who said they used Duolingo to learn that language. Am I extrapolating too much? I think the sample size was pretty good.
The correct comparison would include the effect size on language learning of using Duolingo instead of scrolling through cat videos. The effect size appears to be close to zero. And without considering in the analysis the long-term negative effects on the self-perceived ability to learn a language after spending hundreds of hours using Duolingo and being able to simply say "Hola" in Spanish, which may make the use of Duolingo a net negative on lifetime language learning.