What happened to structured language-learning programs like Assimil?

I’m curious about something: why did structured self-study language programs like Assimil or the old CD-ROM courses mostly disappear?

Back in the day there were a lot of fairly complete language-learning programs: Assimil courses, Rosetta Stone discs, “Tell Me More”, etc. They usually had a clear progression, dialogues, audio, and sometimes interactive exercises.

Today it feels like most of that ecosystem has been replaced by apps (Duolingo, etc.) or scattered online resources. But those don’t always offer the same kind of structured course with a clear beginning-to-intermediate progression.

What surprises me is that with platforms like Steam, mobile app stores, and easy digital downloads, I would have expected more of these kinds of programs, not fewer. Instead it seems like many of them disappeared or moved to simplified apps.

Is it just that the market shifted to subscription apps and mobile learning? Or are there still modern equivalents I’m missing?