Exactly. It is in companies' best interest to keep the device support as short as possible as a way of planned obsolescence, so they can somehow convince consumers (especially the rich western ones) they need a new phone every year (or two). In truth, for the majority of the users, a flagship should last for at least 5. It's not like what we do on phones get computationally more expensive, except the bloat and lack of optimization (both the OS and apps, due to unnecessarily fast processors).