The sheer volume of legacy software prevents this from being realistic. Microsoft's commitment to backwards compatibility has reaped rewards for them. Any restrictions would have a user-controllable toggle.

If APIs prevent programmers from stupid shit the devs would encourage the end users to blame Windows and, more than likely, turn off the restrictions. (Case in point: User Account Control and making users non-Administrator by default. I've dealt with so much shitty software that opens its install instructions up w/ "Disable UAC and make sure the user has admin rights.")

There has to be a point you draw the line and say "Dev, grow up and learn about the platform you're using." An app that required users to be root on a Linux machine wouldn't survive community outrage. Windows doesn't have that kind of community. (Try arguing with a vendor about idiot practices in their app and watch their sales gerbil attempt to end-run you to your manager...)

My Steam Microsoft Flight Sim requires admin rights, so clearly this is a lost battle. We just need to have containers for every app.

We may just get that. Microsoft's attempt to introduce sandboxing with UWP/msix was ignored by developers. Since then MS has added Windows Sandbox to Win 10 Pro and up, essentially disposable VMs for running sketchy software. I wouldn't be surprised if a couple versions down the line we get the option for more permament app-specific VMs, with integration into the window manager similar to QubesOS. A lot of groundwork for that already exists for WSL2, like more efficient memory use between VMs and shared GPU access.

What if Microsoft limited these APIs to programs with "Compatibility Mode" enabled? (And—this may already be the case, I'm not sure—made it impossible to enable compatibility mode programmatically?)

I feel like this would create a strong incentive for modern software to do things "properly", while still allowing legacy software to run (albeit with a couple of extra clicks).

Look how long we're still dealing with software that requires Java 6/7/8, and all the security issues that come with that. Servers/Appliances with IPMI remote consoles that do not support HTML5. It's easy to say "Replace the equipment" but our budgets don't always allow for that.

I think Microsoft's commitment to backwards compatibility is awesome. But it would still be better to at least get newer apps working the right way. Even in the event those legacy apps remain in use for ~forever, at least there would be fewer of them.

See, I disagree with that. The computer is an arbitrary command execution machine. It does what you tell it to do. Don't tell the computer to do stupid shit and it won't. There are plenty of valid use cases where you want to use the capability of the computer without some arbitrary OS policy preventing you from doing it "because some programmers are irresponsible."

In a world of various medium-trusted apps that I don’t love but still have to use to get my job (or a bank transfer etc. done), that model doesn’t really work for me anymore.

Users aren’t “telling the computer what to do” anymore for the most part, third party app developers are; this puts a lot of responsibility on the OS for protecting the interests of its user against that of a malicious or careless app developer.

Of course I want to be able to fine-tune that protection, but restrictive defaults make sense.

I don't think this is fair. Linux and Mac used to operate in generally the same fashion. Only recently have they started sandboxing stuff.

Windows doesn't have the same privileges because they are forced to maintain backwards compatibility.

It's just as bad there with everyone randomly shoving dot-files in my home directory instead of using ~/.config, ~/.local, ~/.cache, and friends.

Just to name a few in my home dir ... aws, cargo, dotnet, yarn, vscode...

All of these narcissistic tools are pretty annoying.

40% of those tools are majority controlled by Microsoft...