Qualcomm provides 8 years of support from platform launch. Android versions are not locked to kernel versions. In general, new Android versions do not require

Qualcomm provides 8 years of support from platform launch. Android versions are not locked to kernel versions. In general, new Android versions do not require new kernel versions. In practice, all kernel drivers are open source including for Snapdragon, Exynos and MediaTek. The kernel drivers can be ported to new major kernel versions regardless of whether the firmware and drivers are still supported. The benefit of updating the kernel and kernel drivers without firmware and userspace driver updates is very low. Rewriting the userspace driver code as open source code on top of the kernel drivers is also entirely possible. It's a lot of work and there's a lack of a security motivation to do it due to needing up-to-date firmware with patches for serious remote vulnerabilities and other issues.