In terms of arch vis, it all depends on what part of the production line you are in, meaning, either in the 2d or 3d team. 2d, to create the super quick images ( half a day - 1 day - few days and the amount of changes are super annoying ), and 3d you guessed it ( Time, maybe a day to months, regarding super realism or animation ).
However as visualisation is becoming easier, there is a merge of both requirements regarding the Artist to now be versed in both 2d and 3d. Only a few can do this. If you work for an Arch firm, once again depending on its size and projects, you will be producing super fast imaging and probably no realism at all to images such as - Mir - Luxigon - Dbox - but even these are considered the end result of imaging - Final advertising imaging. So a project could go through 20 internal images over a period of a year to then be eligible for few final advertising shots, which is then given to the named companies.
If Freelancing, no one cares as long as you can show what you can produce, but even then as you mentioned, you need a business model, how are you going to beat all the other super good freelancers?. Considering, the new trend where companies are creating their own teams, as its probably half the price in terms of wages per staff.
I used to use vray and now switched to corona. The senior partners or architects do not care what I am using, all they care is whether what they envisaged is what they can show the client.
Better to learn both, and I still don't even know Max or Vray in and out, but the work is always produced.
