Also humans are very expensive too, and in many places starting to become a more limited resource. If we look at a huge number of countries currently, many are at risk of population collapses. Japan being the poster child here. If you want more human brainpower you have to convince humans to breed, then dump a huge amount of resources in to that child for nearly two decades. After that you hope and pray they actually want to work at solving the problems in the world instead of playing online all day with their Waifu Replica.

From a historical point of view, computing was expensive and rare, the idea we'd have massive warehouses full of servers connected to a global network was but a dream when I was a child. A single computer (large) computer would have cost as a much as a house and had less power then what you're surfing instagram on in your pocket.