So, many users of AutoCAD either don’t know about Paper Space or don’t know how to use it.
There are many reasons for this, people who have used AutoCAD for many years and they learned it 20 years ago and it did what they wanted so they haven’t continued with learning new techniques.
Others have seen it but don’t understand the benefits or feel that they just don’t need it.
All of the above are reasonable arguments but this doesn’t mean they are right.