I still remember in the late oughts, when Mac software updates came out (say, 10.x.1 or whatever, Safari updates, etc.) an app called Software Update would tell you about them, allow you to click to download and install what you wanted, the installation all happened in the background while you worked, and then at the end the SWU dock icon would bounce to prompt you to restart when ready. Guess what? quick option-right-click → Force Quit on the app would shut that up, then you could go about your day and reboot when you were ready.

Today, the Mac harangues you every time you wake it about the updates, then to apply them, you must reboot immediately, and stare at various Apple logos and progress bars for an indeterminate amount of time (no estimates offered).

Modern macOS updates take forever too. I had one clocked at 40 minutes! In that time I could reinstall Ubuntu 4x over.

On what computer? Actual modern macOS updates takes some initial time indeed, but in the background! The reboot phase is not very long.

As far as I can tell, the updates that require a reboot don't do anything in the background now (prior to the reboot), besides downloading.

They do much. They spend usually around 20 minutes doing stuff before rebooting.

2018 MBP.

Ha yeah, IIRC macOS updates on Intel are slower (and not only because of the processor and/or disk, but because of the whole architecture).

I have VirtualBox VM of Lion. I use that for making 32 bit x86 builds of TXR for older Macs. (I ssh out to the Compile Farm for M1 on newer MacOS.)

you are supposed to say it's snow leopard