OP was talking about that they now have and pursue the intention of upgrading the kernel during the lifetime of the device. Instead of device launching with LTS kernel, which is supported for many years upstream, and always using it, instead LTS kernels are supported for 2 years (or extended like here), and the devices keep moving on to the next lts branch during their lifetime (usually not immediately, but after the regressions fixed for next branch, tested well before that in avf VMS etc)

In practice upgrading kernel can easily cause performance regressions and cause multiple other issues (reduced battery life) so there's a lot of risk for zero reward for an OEM to do that.

After all, they're on the hook for not breaking users already working devices and don't get anything by risking lawsuits and recalls.

I don't personally mind summaries (generally), but this isn't even a (useful) summary, it's effectively the same information as is in the title.