I think they just expect a higher return than smaller start-ups. I mean, if Google tries to make a new service and it's 'only' generating a few million in reven

I think they just expect a higher return than smaller start-ups. I mean, if Google tries to make a new service and it's 'only' generating a few million in revenue, that's not very exciting and they'll either i. directly kill the service, or ii. gamble with aggressive methods of growth that likely kill the service. Meanwhile, give a start-up with 5 people a few million in revenue, and they'll be jumping with joy at their success. Plus they'll have a lot more passion, and more carefully manage risk while growing the business.