Imagine you are starting a concept for an housing block. You are just starting to "shape it". You don't really know if it will be a square or a rectangle or even a more complex polygon. If you use BIM (e.g. Revit), you'll need to define what wall is exactly made of, what kind (and brand!) of window is it, etc, since the beginning.. you don't even know yet what the building will look like! It's completely nonsense and an huge incentive to repetition: you use what you already have in your library once it is a massive hassle to create new objects.
When the project is settled and approved by authorities, then and only then, may pay (depending on the scale) to convert it to BIM: you'll get 3D renderings, bill of quantities and a realtime model of the building out of the box.
An analogy for HNers: Autocad is a text editor (emacs kind), BIM is an IDE.
I think the reasons it is still popular are:
- People who learnt to draft with pencil and paper are still around
- Legacy, still so many drawings that they don't want to have to remodel. The open format exports are never perfect.
- 2D layouts are just practical for a lot of industries (electrical, HVAC, MEP, etc) where they are just need to convey connection information or everything is nice boxes on planes and they don't need spend more time extruding out a 3D when they can just easily just draw an arrow and go "AxBmm". But apparently Revit, which haven't used, is becoming more popular int the MEP/HVAC space apparently?
I know my friend has lots of drop in templates and scripts that they have built up over the years.