I'm not talking about "the community". There are multiple manufacturers/distributors of Linux laptops. They do nothing to stymie the flow of updates, even though your assertion about selling new hardware would theoretically apply just as much there.
However with Android, companies sell 100s of millions of devices to consumers that are more concerned about price point than updates. There just doesn't seem to be the incentive for OEMs to care about it, if the majority of consumers refused to buy devices based on old OS versions or ones that didn't get updates, those devices wouldn't get made.