You're not the average user if you have auto updates disabled. Notice you also said "some" apps, well, most do need to keep up with OS updates or fall behind.
I did not claim to be the average user. Most of my apps do not get updated unless they rely on APIs that force them to update. Furthermore, I have several android apps I published over 15 years ago that still function without updates on the newest version of Android.
What updates do you think need to be made to not “fall behind”? There aren’t many other than things like integration with Google Play services or App Store subscription billing.
