Two thirds quit within three months, and difficulty is not the reason
The progress is real. It is just invisible, and invisible progress feels like none.
Around 65% of people who start a language online stop within three months. When asked why, they rarely say it was too hard. They say they lost the habit, or that they stopped being able to tell whether it was working.
There are two danger points. The first few weeks, when there is no habit yet. And the intermediate plateau, where the beginner gains stop arriving and nothing obvious replaces them.
Both are the same problem underneath: you cannot answer the question what can I do now that I could not do last month. The effort keeps happening and the evidence stops.
Which is why every number on this site is one that moves and means something. Not a streak. Not points. The share of ordinary speech you can follow, counted from real corpora.