As someone who spends a significant amount of my working day developing HMI/SCADA screens, I would agree that it would be a huge headache to lay out an entire screen or even a complex section of a screen in an vector graphics program and embed it into a Perspective view only to have the customer’s factory layout change a month later and have them ask you to redo your screen. 
When I use SVGs, I try to break them up into the smallest, most reusable sections (usually at the device level) to help retain layout flexibility for the future. I tend to create a template view for each device type that contains my graphics (whether SVGs or simply just labels with some creative application of style classes), embed them into a coordinate view where needed, then join them using labels or containers as your “piping” or “wiring.” I usually set up a style class with a set background color for all of my piping, then it’s just a matter of adjusting the coordinates and sizing to get the necessary layout. If devices move in the future, it’s just a simple matter of dragging them around on screen and then adjusting your piping/wiring to match after the fact.
Of course, it is entirely possible to quickly create device graphics natively in Perspective without SVGs as well. Everything in the screenshot below are either labels or containers with some styling applied to them:
Your mileage may vary, just saying that a lack of traditional drawing tools is not the end of the world.