Weird hypothesis, but is what WeWork brings to the table that Regus doesn't is Silicon Valley brand recognition? Not that I'm in the market for office space, but I haven't heard about Regus until this comment.
I think it's down to the customer. There's a post below about somebody being reassured "it's a We Work" office they'll be in.
When I've looked for a job, it's never entered by head to ask who manages the office (my assumption is that it's my employer and if I'm not happy, I'll take it up with my employer).
I can see if you've often worked in offices not run by your employer, you might have learnt to ask - but would think that's a small pool of people working frequently in shared spaces, having worked their frequently enough to have a preference.
Back to the OP - it's not a "hypothesis", this stuff's been going on for decades. e.g. ~2000 I was working in Paris and visited our local guy in his local office on the prestigious "Champs Elysee" no less. I went down the "Champs Elysee", then through a small door behind two shops, then walked back a couple of hundred meters, then through a warren of rooms, then in a room off a room, there was a desk... and that was our office. Hundreds of people all working at this prestigious address - we must have been silver-class as we had our own physical desk.
If you went right back to the entrance door, there was a receptionist you could specifically pay to 'represent you for the hour' and a set of very swish/generic meeting rooms you could pretend were yours to visitors.
Probably, but that knife does cut both ways. I know a number of people (including myself) who wouldn't be willing to use a WeWork facility again.
Among the people I know who dislike WeWork, there are two main things that they complain about: the surveillance, and the actual environment.