While we're at it, lets stop bundling UEFI.

I'm being slightly absurd here since you need some sort of firmware to simply start up the computer and install an operating system, but here is my point: to most people, the operating system is part of the computer. The computer is simply an expensive brick without it. On top of that, a lot of the negativity towards bundling Windows originates from Microsoft's past monopolistic practices[1]. We certainly don't hear many people criticizing the bundling of macOS or iOS on Apple products or Android/Chrome OS on Android devices or Chromebooks. (There may be people who want to load alternative operating systems on these devices, but that is different from criticizing the bundling of the OS.)

[1] Is Microsoft forcing hardware vendors to install Windows even a thing these days?

It makes sense, if manufacturer provides support for Linux on the same laptop SKU. But that's very rarely the case. So selling laptop without OS seems like selling half-working product. When you're buying a car, it comes with a lot of software. ECU software, multimedia software (sometimes it's Windows CE) and so on.

I saw laptops selling with FreeDOS but realistically speaking I think that majority of these laptops end up with pirated Windows, so all it provides is increasing level of piracy.

Ideally laptop should provide a choice between Linux and Windows on the first boot. And easy way to buy Windows license if user chooses it.

1. There are plenty of computers sold with Linux installed.

2. You absolutely should build the computer yourself. You get a much better computer with best of class parts. And you learn something.