Yeah ditto. I don't know when it happened, but the Coursera courses I tried at first (around 2012 I think?) were very high quality -- I thought it was clearly a competitor to traditional brick and mortar.
Then a few years later, checked it out and there were thousands of courses, many clearly without as much thought or effort.
I am not as familiar with the other online schools that focus on quality (like WGU). I am surprised they have not eaten traditional schools lunches, since the actual quality of instruction is often very variable (I am a former professor, for the most part profs have little oversight in how they run classes). Market for lemons maybe?
Another aspect I am surprised at is that the big companies have not just started their own schools. UT-Dallas where I was at for a few years was basically started to help train up folks for Texas Instruments. (RAND Pardee school is kind-of an exemplar, although that is not focused on software engineering.)
I debate sometimes I shouldn't bother with hiring seniors and just train up everyone. If you have 10k software engineers does it not make sense to just have that level of training internally?
Unfortunately the get rich quick/grifter community realised that online courses was a way to make money.