I usually get at least 2 major updates (complete Android version update; like from Marshmallow to Nougat for example) on a flagship device and several minor ones. The Google phones are usually one step ahead of the pack (Pixel is on 7.1 vs the V20 on 7.0 for example) but the bottom line is, by the time the V20 stops getting updates, you're probably already going to be ready for your next device upgrade anyway. For most people (myself included) that's not going to be a deal breaker. Unless you want to stay with the V20 well past 2 years.