Needed as in must have or nice to have?

There are tons of devs creating tons of tech for the sake of creating tech. Cryptocurrencies come to mind, or all those half baked government automation projects where the digital version is in the end slower and more error prone (plus with limited or no recourse in case of failure).

And secondly, sure, they are, but what happens when you have 10 million devs and 8 million dev jobs? Past success is not a guarantee of future performance. Detroit and the car company cities and towns were amazing places to live in, and car engineer jobs were great, decades ago. Until they stopped being great.