I'm sure they worked for a paycheck, providing the critical infrastructure needed to property manage that many office spaces and customers.
WeWork has tens of thousands of customers who for the most part are able to seamlessly come and go, check out conference rooms, pay for various one-offs, and their membership fees.
Did they need 1500 engineers to build all of that, no. But when you take venture capital in the expectation of growth, you have to grow.