I have a hard time believing that there's going to be a robot that will be able to do plumbing or electrical in an older home in the next 20 years, let alone the next 5. Will they maybe have something that helps run wire through a crawl-space? Sure, maybe. Maybe even something that could run PEX tubing under a house - maybe. But they're going to get into situations where they get hung up, stuck, etc. and require a lot of skilled help. They could be a labor saving device, but they're not going to completely replace the plumber/electrician for a long time (on existing construction - it's an easier problem with new construction because it can be designed in such a way as to accommodate robots. Still, there's a lot of existing construction and a shortage of both plumbers and electricians).