The author didn't bring up the point that many of those services became successful (not yet profitable) because they were free. The years when they had no ads and charged nothing are considered loss-leaders in order to build a large network, because their services typically benefit strongly from first order network effects.

Google didn't always have such an indisputable business model. Who knew search was so profitable? Would it have been as successful if it started charging users right off the bat, or covering the results pages with (irrelevant) ads before contextual ads were developed?