Comment by aa-jv

You have to take into account the fact that a lot of Qualcomm's chips are intended for military/industrial complex applications. They're not just a consumer-chip producer.

Having an installed user base always on the latest firmware version cuts down on support costs. Its a hidden cost but a real one: when a user calls customer service with a problem, you're losing money - anything that reduces the amount of time spent debugging the issue, is a win. This means that if the support engineers can rely on the fact that users will always be pushed forward in software releases, they can focus on contemporary issues/uses cases rather than having to maintain - for years, often - an archaic list of prior versions/faults/issues.

Its not just the case that these eFuses' prevent "ownership" of the firmware by the user - though that is a consideration - its more that, by disallowing downgrades to prior firmware releases, a mechanism is in place that organizationally promotes improvement in the product quality. Well, that's the theory - that the latest OS is always an improvement - and believe me, we software engineers work hard to make sure that is the case. It occasionally doesn't go according to plan and users feel compelled - for whatever reasons they decide - to downgrade to a prior version - but as a software engineer, I much prefer to operate, knowing that my end users will always be encouraged to have the latest and greatest (hopefully) version of the firmware.

Support is a sunk cost. Supporting older versions is a self-imposed force multiplier of that cost.