That’s not a new thing - I’ve defended my masters degree in computer science, on this subject, 10 years ago. At that time I was already working for guys who specialized in these products.
I never worked directly in Gensler office but taking into account the amount of projects we did I wouldn’t be surprised if they were end client at some point. To give you an example, there is installation in Heineken museum, software for which was done by me, but I never worked with anyone from the Heineken itself. It’s a normal thing that you have a long chain of intermediaries where you work with media partner of marketing branch of advertisement agency who is hired by real-estate developer. So when you get your floor-plans and sketches they are not even coming from architects directly. It’s very rare to work with the end client directly as it’s not their specialization. Hilarity of this chain becomes obvious when several times you get exactly the same RFP from two different clients.
I’m glad to hear that nowadays they are trying to make such projects themselves. But I wouldn’t be surprised if it’s done more for self promotion than actual service which they sell to the client. Perhaps they do it to get a competitive leverage, which again means that this product is still not a standard in their covered territory. Their capability to sell architecture service doesn’t mean anything with this media. I’ve seen AAA studios failing in this business miserable. It’s a false assumption to think that, for example, if someone like Pixar is good in CG, then they will definitely rock in technical visualization. They can be using similar tools but the core business needs are different.
I don’t know that well business model of architects, most of our clients where real-estate developers, advertisement agencies and “competitors/partners”. Their budget is most of the time provided by investors and we were hired in parallel with architects. The fact that agency gets a 5 mil in marketing budget doesn’t mean that they are ready to finance several month of development for interactive product and spend 80k on it.
It’s about the end product after all. It took us years to find a proper approach to clients so that interactive real-time application wouldn’t be replaceable by cheaper visualization materials. The choice of the engine is the least concern in this area when pretty much everything can be outsourced dirty cheap. If you happen to work for one of the largest companies and they don’t care so much about cost and time to build on interactive projects then good for you. But this is not the situation where 99% of people will end up, this is why products such as Lumion are so popular. The longest development time we ever had was for one of the emirate projects were we spend whooping 3 month! to complete everything 
This was with already nicely optimized production pipeline where things like import of geometry and assigning of materials was automated. Lightning and shadows were standardized and had to be tweaked only for specific mood when necessary. Recording video and taking annotated screenshots could be done in application itself by end user, instead of recording it in editor. This is where you win by having a superior product which is based on superior tools, not on a free engine which everyone in China and India will be using for games and archiviz in a matter of few years.