This is entirely Qualcomm's doing. If they supported Arm SBSA/UEFI+ACPI like some other Arm chip companies (e.g. Ampere) you could boot a generic Linux (or indeed BSD) Arm distro on their chips no problem. Controlling the entire platform is not necessary, just follow the standards.

AFAIk this has nothing to do with Qualcomm but with vendors and Microsoft.