On the other side of this controversy are developers who want to use Vulkan and other features which require hardware support, and they are tired of dealing with runtime API capability checks (A.K.A. "fragmentation"). You cannot have backward-compatibility for these features if you require support for them in hardware.

This is more a cavalier attitude on the part of Qualcomm who do not support their own hardware for a reasonable length of time, and who do not foster open-source driver development which would at least allow the community to bring new features to older hardware in some cases (Vulkan being the prime example).