So you show me a video of a robot walking for a whole 50 seconds, carrying no load and using no tools in any confined space?
Right now robots are still in the research stage. If you really feel a need for a toilet-installing robot, by all means suggest that to Boston Dynamics and have them develop it.
What did that robot cost to build and develop? How many years could you pay a plumbers salary instead of developing that robot, which can't do the job we are talking about?
They won't because there are jobs where it's just not economical to do so. Robots cost money to design, build and maintain, alogrithms also.
If you get an order for 10 of something you're probably not going to spend $100m designing a robot to do it.... Unless you've got a bunch of dumb "investors" that are going to pay you a multi-million dollar salary to work on it for ten years and then fail.
Not all engineering challenges are trivial and can be solved in a few years. Just as we don't all have flying cars or portable nuclear reactors, sometimes things don't get magically 100x cheaper and easier just because someone with no experience in the field predicts they will.
Look at the nuclear powered airplane program. Or the Boeing SST. Or fusion reactors.
Only reason why it might cost more now to build robots instead of hiring human labour is because there is no economies of scale on robot-building yet so all the resources being put in to produce a robot is relatively higher. Once robots can be mass-produced I am sure the cost will come directly down and would eventually cost less than human labour. Like I said robots are still in research stage right now.
There's a reason we still build houses out of wood instead of boron-epoxy composite.
Actually it's the 3D-printed houses that you need to be "scared of".