Why does not the ipod classic have bluetooth?

Why does not the ipod classic have the bluetooth to answer the iphone?

I don't want the bluetooth to listen music,

but I always can not hear a ringtone from my phone during enjoy music with ipod classic.

The bluetooth in the ipod classic will provide really big convenience to the person who love music with th eipod classic.

How about developing the technology to connect only Apple product?

I don't want the bluetooth technology for the headset because of bad sound quality.