Saucelabs appeared almost simultaneously with our internal Selenium Grid. However the main obstacle is certainly the price. We require a lot of Selenium sessions. Really. For example our usual case is to have 2000 browsers running in parallel during hours. Total number of sessions per week can be dozens of millions. An average RPS can achieve 400 per each GridRouter node. Not sure if Saucelabs can deliver such quantities of virtual machines. Anyway this could cost a fortune to the company.