I can promise you there are many, many professional musicians who will be first in line to upgrade their Mac.

I’m a professional programmer it’s not like I test if my mouse or keyboard will work with a new windows update.

It's very well known plugins break with OS updates. The vendors usually send emails warning against updates. Someone making music at home for fun might update on day one, but no professional studio will.

None of the pro musicians I know leap to update their OS like that. Some of them even keep their music machines perpetually offline. These computers are tools for music which just happen to run some OS.

Logically yes, but anyone who’s been doing it for more than a couple years has been burned by an update at least once and won’t easily make that mistake again.

The mistake here is not the apple update but lack of backups.

The mistake here is that assuming things will forever remain the same and thus you don’t need to update your software, when security enhancements require it.

Even if you properly backup everything and can downgrade after an update, you’re still burned by an update if it breaks your software. Which is why most musicians will be at least a major OS version behind, giving vendors the time to update.

Maybe amateurs…

Professionals tend to keep a stable system running for as long as possible. The first studio I worked in had a B room that was running OS 9 at a point where OS X had been out for 7 years.

My current setup at home is a 2010 MacMini on v10.13, using a firewire interface. I plan to keep it running as long as possible.

What do professionals do when the hardware fails? Do they have regular backups, then buy the same hardware on ebay and then restore the "golden" setup?

I recently tried to reinstall an old MacBook 13" that had a hard drive replacement. I couldn't log in to perform the install, Apple servers were throwing me an error. The only choice I had is to put another OS on it.

Pro Tools has been broken on virtually every major version release of MacOS as far as I can remember, I don't think pros are the ones eager to upgrade their OS. They do it begrudgingly as late as possible.

I follow the audio engineering subreddits and 'do not allow your computers to update' is an extremely common epithet, and updates wrecking a booked session is a very common complaint.

We're talking about guys who will use a trackball simply because it makes sure their cursor will be where they left it. Their demands for stability are beyond even what I have seen doing sysadmin at a hospital.

I DJ for money though I wouldn’t say professionally. I have a separate 2015 MacBook Pro with all my software installed and it’s not connected to the internet except to transfer new songs and manual updates to it.

Sometimes... programmers are worse users than general users.

Yep. Truly a testament to how bad modern backwards compatibility has gotten.