I agree that the money is in advertising and marketing but you can focus on architecture nonetheless. I understand architects alone may not have the budget for rendering but their clients might have it tho! The final buyer of the design will probably at some point request a visualisation of the project. They’ll ask the architect/designer to contract a 3d rendering studio if the architect can’t/don’t have the time to do it in-house. I guess that’s how it works. Architects also need high-end rendering sometimes to have a chance at winning competitions. Of course these contracts must be hard to get. It’s not for the 250 000$ bungalow tho.
I agree with you that it may be important to have knowledge outside of 3ds max and architecture. Doing a movie without being able to add some motion graphic is not so good.
I’d say, aim for architects, industrial designers, interior designers, property developpers and you should be able to find clients. The real clients asking for viz isn’t the professionals, it’s you and I buying houses, condos, expensive luxury appartement, etc. If there’s a demande for that, we are in business. What do you think?