In archviz most renders are comissioned for competitions or client presentations.
In competitions there is a limited budget, which is reflected in the price offices/clients are willing to pay for a render.
(no-one working on archi competitions is well paid; consultants often work for free (with promise of prospective work), architects and interns are underpaid and work around the clock.)
For the time spent the 3d guys is better paid than architect, i.e. for ~1500 you can pay a junior architect or 3 interns for a month .
As for the visualisation itself, for competitions the overall atmosphere/impression of the image is more imporant. There is limited time and many changes until the last moment.
If you look at companies specialising in competition archviz, they are not the same people doing catalogue visualisations for developers' publications.
3d rendering has become much more approachable, even thanks to renderer like Corona (with great support, resources and community for learning), virtually every design/archi student is learning rendering today.
For students and enthusiasts it is a bonus if they get anything for an image.
For startups it is understandable they cut prices to get new clients on board.
Image quality is usually good enough and hence higher cost isn't justified for most purposes.
It mimics photography industry after the democratization of digital reflex cameras, where everyone has become a photographer :-)
Demand for high-end renders still exist, but it is a different market to most archviz today.
At the end of the day, architecture/construction is not about CG skill, the render is not the end product, but a means of communication. Renders are not comissioned as work of art.
