1. The growth period for distribution for digital ads is basically over. We're firmly in the consolidation period and Google and FB have taken the majority of the digital ad market. There's basically no room to grow into, it's just about eating up the boundaries and new entrants.
2. Regulation seems to be coming for user data and these big ad platforms. Google and FB are trying to play the regulatory capture game so they stay in business, but again it's not a growth business - it's playing defense.
It seems like Google is best positioned to actually pivot to selling enterprise/consumers services with GCP and their services offerings. They also have an opportunity in hardware.
Facebook on the other hand seems to only have hardware as it's future, but they are up against Apple and Samsung and Google for that.