I think that you're right, but that's only for a small portion of the user base.
My observation is that most people just let upgrades happen automatically. Then, they suffer with the side-effects of an operating system trying to do more with a fixed level of hardware capability. Note: Software is not magic, even if it seems to be.
A subset of the above will just use this as an excuse to buy that new phone that they just know they need to have. I don't know if Apple deliberately plays to this, but it certainly appears that they at least look the other way.
Then there's people who follow sites like MacRumors. They get worked up when things don't work the way they should, or the way they want them to work. (Notice the subtle difference there.) The software is not magic comment still applies.
However, having the ability to roll back your operating system version to where you previously were happy seems most reasonable. I personally don't understand why that's not permitted, especially if it's a backup on your own storage. You could try the new operating system, determine if the performance hit is worth it on your hardware, and make your choice. I guess that's so they reduce the number of operating systems they need to support. Except for the people who opted out of upgrades, of course.
Based on some recent experiences and observations with regard to Mac operating system upgrades, it does seem that Apple is offering upgrades that actually break things, and then either deny that it's broken, blame you the customer, or tell you to upgrade to Big Sur and/or buy a new computer. I say, heck'em.
Think about this logically.
Why does Apple offer new operating system versions each year? (This was not always the case, btw) Primarily because new operating system are needed to take advantage of whatever new hardware they want to sell you this year.
So, why do they also make it so the new operating system can be loaded into device a couple years old? I think it's primarily to keep people engaged. (I'm not counting security or bug fixes.) It's a marketing tool for them. They don't make any money directly from upgrades. In fact, it must cost them a lot because of the distribution, the needed support, and the regression testing they sorta do. (Mac operating systems used to be distributed on CDs, so they didn't come for free. But, for the price they charged, I have to believe that they made profit beyond the cost of buying CDs or DVDs, packaging, shipping, and profit for a dealer. After all. what do DVDs sell for?)
Think about how this works for iOS devices. When you get a new device, there's a new operating system in it. It's the latest version, at least without taking into account very recent upgrades that were offered after the product left the factory. Then, most people automatically get upgrades unless they go out of their way to opt out. (They still get nagged - the parallels with privacy concerns are too funny to discuss.) If an upgrade doesn't work well for a customer, they have just a week or two to go back. And, they can only go back one version. Your device is entirely under Apple's control until the day when they say, "We're done! You're on your own! Don't look to us for help."
That all seems crazy.
Having software upgrades that are specifically aimed to take advantage of new hardware also work, sorta, on older devices is nutty. Maybe on last year's hardware, but not much beyond that.
I'd be much happier if they provided bug fixes and security upgrades for older operating systems, even if it there was a modest cost associated. Maybe if they got some revenue form it, Apple would devote more resources to fixing those than they do. AppleCare is currently between about $4 and $12 per month for an iPhone, from what I gather. A Mac is about $10 per month. That's for hardware, too. Why not a flat fee of a buck a month for operating system upgrades after the first year? Or, maybe, 99 cents, like iCloud storage?
