But plenty of "non-WeWork" office space offerings have already been like that for decades. They'll provide janitors, receptionists, etc unless you opt for spaces without it to run your own.
Cynically, those companies have the downside of needing to make a profit. WeWork strikes me as the sort of company that would happily take a massive loss, just to get to brag that Stripe and Facebook use their services.
That strategy works great, so long as you have unlimited funding.