I’ve only done 1 paid contract for an industrial designer (marina design) and it paid well. For now. Your clients aren’t just architects…expand. Interior designers, urban planners, industrial designers, property developers, even manufacturers etc.
A friend at a company showed me renderings contracts he had with other artists or studios and I was impressed. Spending 20k$ on a couple images and short animation. Dunno if it’s common but there are definitely clients like that around and I’m going to find 'em 
With unreal I could’ve done the same, minus the rendering costs
I say if you enjoy architecture and 3d go for it but don’t limit yourself to the Architects alone as your clients.