Microsoft requires Windows 11 computers to have special new hardware that not all computers have. Security updates for Windows 10 ends in 3 months. Many people are faced with a choice of buying a new computer, or installing Linux on their current one to save money. Others realize how much Windows 11 sucks shit and switch because Linux is better.
Gaming on Linux has gotten a lot better recently. For many people, this was the main thing holding them back. Software support in general is better than ever.
The short version is 2 reasons: