I've rented in the UK for decades and I've never had a dishwasher or space for one. Friends haven't bothered with dishwashers until they had kids, and then they needed to create a space and add some plumbing.
Dishwashers in the UK seem like the opposite of ubiquitous. Maybe I live in a strange bubble.
Maybe older builds that haven't been updated wouldn't have any space for one as you say, without re-jigging cupboards, so maybe people do. But then you're losing work surface for it..
I lived in Paris for a while. Large appartement have dishwasher, but in single units, it’s uncommon.
I remember looking for solution like that for a renter in a small place without proper plumbing to accommodate a dishwasher.
I also see a market for the so called tiny house folks or full time RVer.
I don’t find that particular product appealing too much, but I would like to see more like that. And I know folks around me that would buy one if it’s was more open and fixable.
Like rearranging plumbing/electrical however you want.
Whether landlords use this advantage for tenants quality of life is a whole other story.
And as a singleton, you don't often make enough dishes to justify a full load either. (although a twin drawer dishwasher would work a treat there)
I'd gladly use a tabletop dishwasher if I didn't have one, otherwise I'd have to use paper plates and plastic cups.
I had to pay it myself once in 2013. It was a sunken cost I was ok with given how cutthroat the real estate market is and how much I hate to do dishes.