[freedom-fries]

The economics of hardware unfortunately do not allow "niche" and "low-cost" to go together. The market for PoE doorbells is very small as it is, so the unit-cost will be high, which makes the market too small for anyone to serve, except probably DIY.

[sirmoveon]

With the amount of PoE IP cameras out there, I find it hard to believe adding a button would take much R&D.

[jasonjayr]

A good chunk of the IP cameras have user-exposed pins that can send events when the circuit is closed, as well as detect if a circuit is open (NC/NO circuits). IIRC they are intended to detect if a door is open or closed.

I'm not sure if they are polling those contacts fast enough for 'normal' doorbell use, but it's there ...

[PeterisP]

Trivial things such as injection mold costs (to make a cheap, cost-effective case) mean that low-cost manufacturers avoid adding a button like a plague - we're seeing the exact same layout used by multiple products and in some cases even multiple manufacturers, we're seeing "unused buttons" just as to be able to use the exact same plastic parts instead of having to make a new mold for a new, slightly different part.

Cheap plastic shit is cheap only if you can make lots of them, because the variable cost is low - but as soon as you're talking about small quantities of niche products, the fixed costs dominate as soon as you try to do anything custom physically.