It was a time when federated and unified views were considered the optimal user experience and there were many flavors of the concept at the time (msft had search providers that would let you service any kind of result in windows or sharepoint search). However, 'brand awareness' started to take over. Nobody wanted to be just a provide to an obviously google-ish experience because it makes them easier to replace.

Like with messaging apps, everything fractioned to fall to a zero sum game of exclusive 'experiences'.