You think 9% of all workers will switch to being remote every year starting now? By that logic, there won’t be any non-remote workers left in 15 years. The current number is only about 3% [1], so a more reasonable growth number (although still large) is 0.25%, which means (by the rest of your numbers), only 0.045% of all workers (in the US) each year will switch to WeWork.
I think that's where the error lies. WeWork has no lock-in, there's no good reason to choose them over a competitor and it doesn't take much capital to start a local competitor (and there are many already).
I was looking at offices like this recently and the most important factor was being close to home which had local competitors. When I look at WeWork locations, they're mostly in the CBD, so they're not even attracting anyone with a local office.
[1]: https://smallbiztrends.com/2018/04/2018-remote-work-statisti...