You're both missing one of the more likely explanation.. that nobody gave much thought about how long the device would last. "It's solid state electronics, it'll probably outlast the warranty anyway".. I can imagine an aircon company puts a lot of effort into analyzing the air-conditioning unit itself to make sure it lasts at least as long as the warranty, with good margin. But I can totally see them winging it on an external control device, which was perhaps even a project they outsourced anyway.
I don't think actual malicious planned obsolescence is as prevalent as many believe. A device breaking right after warranty is not a good strategy to get repeat customers. It's also a huge risk if you miscalculated and you suddenly get a lot of warranty cases. You want a lot of margin there.
I've been involved in the design of a thing myself, where something the manufacturer hadn't clearly communicated - and we just barely caught - could have made the device die just around a typical warranty period for such a device. When we found out, of course we worked on this problem to make sure it didn't die prematurely.
I don't think actual malicious planned obsolescence is as prevalent as many believe. A device breaking right after warranty is not a good strategy to get repeat customers. It's also a huge risk if you miscalculated and you suddenly get a lot of warranty cases. You want a lot of margin there.
I've been involved in the design of a thing myself, where something the manufacturer hadn't clearly communicated - and we just barely caught - could have made the device die just around a typical warranty period for such a device. When we found out, of course we worked on this problem to make sure it didn't die prematurely.