There are too many different types of "developers." I read about all these people talking about playing AAA games being a concern on work computers, and that is not something I have ever even considered. A gaming computer that I own is totally separate from a work computer that my company purchased for me. I would expect even a solo dev would want to cleanly separate work and play, but I guess not.
As to why you might still need Windows on a work computer, Office 365 is still limited compared to native Office, but of course Microsoft is pushing everyone to stop using native Office anyway. I still haven't found a way to sign a pdf with a smartcard on Linux yet, which is literally the only reason I still need Windows because of account provisioning workflows that haven't gone full auto yet and still require pdfs digitally signed with a smartcard. The other reason is your employer requires a Windows computer because you're in a big company with an IT department that requires remote management agents, which exist on Linux, but are a lot more mature and common on Windows. The final really obvious reason is you need to target Windows as a platform or both Windows and Linux and find it easier to put a Linux VM in Windows, especially now that WSL exists and does it for you, rather than the other way around.
I do wonder what hardware people are still having issues with. I can understand if you're using something like Arch that comes with almost nothing in the base system and expects you to know what packages you need for your peripherals, but for a kitchen sink distro like Fedora or Ubuntu, they seem to pretty much just work at this point. I've run them on laptops, with external monitors, external webcams, wireless keyboards and mice, Bluetooth headsets with microphones, eARC soundbars, WiFi 6, smartcard readers, NVIDIA GPUs, using a television as a monitor. Every single one of those things "just worked" the first time I plugged it in.
The only hardware issues I have had in the past two years are:
1. aRGB LED controller software and PWM fan control software only runs on Windows because the vendors don't use open standards and don't make Linux versions of their proprietary software
2. Microsoft Teams on Windows never seems to work with a Bluetooth microphone, but every other program that accepts audio input uses it just fine