Smart home equipment has passed through several incompatible standards in a relatively short period. The churn reflects genuine engineering trade-offs rather than mere commercial manoeuvring.
Battery devices cannot use ordinary networking
A sensor running for years on a small cell cannot keep a conventional wireless connection alive, because maintaining that link consumes far too much power.
Low-power protocols solve this by keeping the radio off almost all the time and waking briefly on a schedule or when something changes.
The cost is low data rates and the need for a separate hub, since the phone and router speak a different protocol entirely.
Mesh networking solves range and adds complexity
Low-power radios have short range, so protocols designed for them pass messages between mains-powered devices to reach distant ones.
This works well once enough powered devices exist and behaves unpredictably in sparse installations, where a single removed device can partition the network.
Diagnosing a mesh problem is also difficult, because the symptom appears at one device while the cause lies in the routing between others.
Interoperability was left to the application layer
Sharing a radio protocol does not mean two devices understand each other, since the meaning of messages is defined separately above the transport.
Manufacturers filled that gap with their own definitions, producing devices that were technically compatible and practically not.
This is the specific failure that later standards set out to address, by defining device types and their behaviour rather than only how bits travel.
Cloud dependence became the common shortcut
Rather than solving local interoperability, many products routed everything through manufacturer servers, where integration could be arranged between companies.
The approach works while both services operate and fails entirely when either is discontinued or when the connection drops.
Local control has returned as a design goal partly because of accumulated experience with products that stopped working for reasons unrelated to their hardware.
Adoption lags specification by years
A published standard does not change installed devices, and a household accumulates equipment over a decade across several incompatible generations.
Bridges that translate between protocols are the practical answer, and they add a component that must itself be maintained and eventually replaced.
This is why a home with a long history of additions ends up running several systems simultaneously regardless of what any current standard promises.
Buying into whichever protocol the existing hub already speaks is usually cheaper than converging on a newer one, since the migration cost falls entirely on the household.