Not every job a plumber does is an emergency situation. I used a plumber to help me setup a backyard project to set up a portable propane tankless gas water heater. I took a look at buying at the parts and pieces I would need, but they needed special tools that would only be used once if I were to buy them. Instead, I had the plumber do it for me with all of the necessary parts/pieces on the truck plus the tools to do it. It cost me less than it would have to buy everything. Now, I just need a cold water feed, and I have a portable hot/cold running system.
Not everyone works all three or wants to do more than one of these groups. There’s different levels of demand, pay, competition at each.
You can shut the entire network off, shower/poop at neighbours places or work, laundry at the local self-laundry shop and brush you teeth with a bootle of water. Inconvenient sure, but it would as much problematic to be denied electricity for a long time: lights off, fridge off, no heating, boiler off… there’s alternatives but the usual way for us is to share a long electric cord by an open window… so obligatory work-and-stay-at-home if you’re lucky to have an appropriate activity.
Get a 5 gallon bucket with lid. Put garbage bag inside. Put toilet seat from broken toilet on it.
Use it, remove refuse if needed, put lid on.
I love the design of it though, I'd never even though about diverting flow toilets, but this design is so simple and elegant.