[pjmlp]

> We're either talking past each other or have a vastly different sense of the issue we're talking about (or both).

My point is that developers always had zero control over the hardware/software configuration of the systems being targeted, it has nothing to do with the ability to upgrade.

Lets say one is coding an application for Amigas. There are 500, 600, 1000, 1200, .... series.

There is zero control over which type of monitor/TV and external devices the respective users have attached to their systems.

There is no concept of device drivers as of today systems, most need to be provided by the application writers themselves.

Again, zero to do with upgrade capability rather with the diversity of the installed base.