I agree — I personally only update when I absolutely have to for an app to keep working (for example when my old phone died I had to get a new one. My older version of Adobe Lightroom wasn’t compatible with my new phone, and the updated Lightroom required a newer macOS, forcing an upgrade).
But… macOS is increasingly nagging about getting you to upgrade; I’ve had to put my machine constantly into “do not disturb” mode to stop the pop ups.
macOS versions well past 12 months out of date are getting security updates. Sonoma still gets updates and even Catalina received one recently.
Yes, that happens sometimes, but don’t count on it. Guaranteed are two years after a major release.
The slow adoption of Twentysix makes me hope that support for the previous systems will last even a bit longer, this time. In any case, I appreciate the major security updates have been warranted up to today to relatively very old systems.
Paolo