Siri & Voice Recognition

My wife and I both have iPhone 13, and she has an older iPhone 11 for work.

On our personal iPhone 13s, Siri will only respond to the "Hey Siri" from the

owner of the phone who set Siri up.

OTOH, although I had nothing to do with setting Siri up on my wife's work phone,

Siri responds to my wife's or my "Hey Siri".

While that might seem to be beneficial, the other night when using my flashlight

via my Siri, I think we nearly had a fire under her work phone. We checked, and

her iPhone 11 from work does recognize my "Hey Siri" as well as my wife's voice.

How unusual is this?

Can all iPhones be made to do this?

When is Siri going to get smarter?

Thanks