Especially when that "stack" is just your operating system. Like, what feature does a new OS like Big Sur include that was previously denied to you on a previous version of OS X? I don't get the eagerness to upgrade, especially after Catalina had proven to be somewhat bug-ridden as well.
Apple often ties their whole pipeline to OS updates for developers.
In the past it's been that developing on the latest iPhone needed the latest version of Xcode and the latest version of Xcode needed the latest version of the OS.
