McKinsey estimated the global market for cellphones would be 900,000 units in 2000.

They were off by 100 million.

Even until the 90s some telcos believed that cell usage would never eclipse landlines which would remain the base of their business. It sounds ridiculous today because cell numbers outnumber landlines almost ten to one and have been dominant for over two decades.

They did. I worked in telecommunications from the late 90s until 2016. The death of the landline and dominance of mobile was a genuine surprise to the industry. The iPhone was the knockout blow.

my most altruistic view : they said it through actions.

Rural areas were the last areas to join the mobile networks.

This is just a practical thing though; why would you build a tower for a community of 900 people when there are still gaps in the major metropolitan areas? It can't all happen simultaneously regardless of how badly we wish it could.