What is with hybrid offense/defense items?

Just going to start by saying this isn't a QQ thread. I'm just curious if there is a legitimate reason as to why this is or if its just because 'thats the way it is'. Only going to be covering complete items as well.

AP/MR: (Athenes now niche at best)

AP/Armor: (Zekes extremely niche)

AP/Health: (Obviously support only)

AD/MR:

AD/Armor: None

AD/Health: (all but BC kinda niche in their own ways)

Is there a reason why an AD/Armor item doesnt exist? Or why is there only one viable AP/Armor item?

The only reason I can think of for the latter is that mages have more viable choices when it comes to AP/Health items as opposed to AD/Health in a traditional ADC build. Of course Cleaver and Tri work on specific ADCs, but ADCs for sure have access to more variety of good AD/MR items.

Could go into interactions with bruisers with these items, but I think we kinda get the jyst of whats good on which AD bruisers.

Anyone want to chime in their 2 cents? Trying to rationalize this here.