In house renderer in the US since 2003, worked for one firm from 2003-2020 as the only in-house 3d guy and was laid off last year due to COVID. I spent about 3.5 months looking for another in-house position, found one in January and I'm back at it with a slight increase in pay and position. As far as whether the in-house position is becoming more rare I can't really say but I agree that programs like Enscape and Lumion are causing firms to re-think the way they produce visualizations. In the past before these programs surfaced the in-house guy was a vital part of the design/marketing/presentation process. Programs like 3d Studio & Vray were difficult to learn and use and as a result the in-house guy had a very secure position, that security is gone now especially if you work for a company that doesn't care about image quality. If you work for one of these companies I suggest you start looking for a place that does appreciate what a seasoned 3d artist can bring to the table.
For all the new people who are just getting into visualization I encourage you to broaden your skill set to include things like VR & AR, video production, Drone operation and anything else you can think of to make yourself more valuable.