In fact for the general software user I think terminal commands are a thing of the past.
But a good command line is essential for replicating more complicating tasks on more than one machine. I still remember when computer magazines printed a ton of screenshots on how to do certain things. A command line can be short, simple and much easier to replicate.
Fixing problems on windows means watching youtube videos and trying to replicate clicks which sometimes break the version is not the same. On linux, you google the problem, find the fix on stackoverflow and just type a few commands.
Beware that copy-pasting from websites may not be safe!
For the general software user.... maybe. Seen advanced users and developers acting like that makes them seem very likely underestimating or ignoring the power of features like history and how you can combine and compose commands.
What is actually left is a tiny group of people compared to all the computer population.
Terminal is a thing of the past. No use pretending it isn't.
Certainly not on HN. You could say the same about assistive technologies, for example.
Also, the current "computer population" still is a distortion. A lot of people started using computers to access the internet and have some entertainment. This is being replaced by smartphones, tablets and smart tv's. So, the advanced users share on "computer population" is (I think) increasing.
You can see some evidence of people using less the "computer" and more other devices: https://gs.statcounter.com/os-market-share#monthly-200901-20...