It is true that many vendors abandon their devices more quickly than I would like, but it depends on the vendor and the "flagshipness" of the device. Also, since version 8.0, Google has made a number of improvements to the modularity of the OS which make it easier for vendors to release updates ("Project Treble"), so the problem has been reduced somewhat
While fact checking my other comment here, it seems like Samsung has been slow to roll out major version upgrades _since_ Android 8. Have other manufacturers improved in this regard since Project Treble?
