Comment by chjj
I don't think it's a strange comment. He's mostly right (and so are you, but I think you're talking past each other). There's nothing wrong with SRS, and I agree with you that it's basically like cheat codes for memorization, but there is a limit to what most people can do. i.e. most people do tend to drop off.
I remember reading some stats from WaniKani (Japanese SRS app) a while back...
WaniKani has 60 "levels" to learn 2000+ kanji. Each level takes about a week (there's no skipping ahead), so the material takes about a year of study to complete -- that's if you're going at breakneck pace, which most people aren't.
According to the numbers I saw on the WK forums, ~8% of users reach level 30 and less than 1% reach level 60... and that's just to learn as much kanji as a 9th grader. That's to say nothing of the grammar and the 20,000+ vocab words you'll need to SRS to truly learn the language, or the thousands of hours you'll have to spend speaking/listening/reading, immersing yourself in native content, etc.
People give up very easily. The language learning community often gives year estimates to reach "near-native level" in a language based on frequency of study. In reality, the process takes a lifetime. I don't know if people truly know what they're signing up for when install those apps and begin studying. It's a lifelong commitment. It's just something you do now, every day.
You can stop at any time of course, and most people do (more than 99% of them apparently).
Learning a language as a hobby is tough. If you don't need the language to communicate and survive in your environment then you have essentially zero real motivation to learn it.
The problem with spaced repetition systems is that it doesn't supply that extra motivation. You're still just memorizing things in a vacuum. If you truly want to learn a language you need to use it to communicate. That means making friends, travelling, reading books, and consuming other media in that language.