Not forever, backports were introduced with Sarge IIRC. And typically versions only appears in backports that are also in testing/unstable, e.g. Linux 6.19 is c

Not forever, backports were introduced with Sarge IIRC. And typically versions only appears in backports that are also in testing/unstable, e.g. Linux 6.19 is currently in trixie-backports but the non-LTS kernels between 6.12 and 6.18 were not available there, nor is the current 7.0 (yet).