So stop using monitors the way I've been using them since 1982?
Yes. Technology has grown and expanded rapidly over those 43 years. You should also be changing with time to take advantage of such technological growth.
Stop using them the way that literally every other screen I interact with functions?
Your other screens can be used to multi task as well. Phones/tablets have picture-in-picture and app split-screen (both of which I use frequently).
TVs are admittedly geared towards single wide screen tasks like the obvious: media consumption. Though some smart TVs will also let you web browse while watching TV. And I'm pretty sure game consoles that facilitate streaming allow you to display chat over or beside the game.
That's what 2nd and 3rd monitors are for.
That's what additional monitors can be used for; but the point is with a single wide monitor you don't have to run a second monitor. You already have that additional space available when/if you want it.
Sure, I'm usually viewing a single window; but there's plenty of times when I want to open multiple applications side by side. I also play games and watch media; both of which are widescreen experiences. You might not need it 100% of the time, but it's there when you do.
That's not so easy when you're using multiple curved monitors with a stand or mount.
You've got tons of screen real estate to work with then; what's your concern? You could mount one vertically, you could use different sized displays, you could stack them.
Nobody's forced you to stick with the setup you have. If you wamt something different, set things up differently; it's your setup. Don't trap yourself in a box thinking you can only set things up or use them the way you've seen others do it. Be your own person.
Perhaps I worded this poorly.
In an office settting; the primary use of a wide display is to have multiple tasks/windows open. An email your composing beside a document you're referencing for example.
My main point here is the additional space is there for you when you want it, instead of being missing when it's needed.
You've gotta cater to the lowest common denominator there unfortunately. Things like this are presented in a simple easy to understand format, so that as many people as possible can get started with minimal help. Some people excel and explore the limits of their systems and what they can do with it; others don't get past 'computer basics 101' while using their computers for little more than a web browser.
"you're using it wrong" is a bit harsh. What you're doing isn't wrong, more like "there's more you could do to utilize the technology you have available".