Well, realistically they’re not the ones providing the updates. Graphene is providing them.

4.5 years also isn't that much. I just replaced my 5 years old phone, but only because it's not actually my own, but paid for by work. Had it been my own, I'd get the battery replaced and the charging port cleaned instead. The battery replacement isn't even that expensive.

Using a five year old phone isn't an issue anymore, they are fast enough that it doesn't matter.