You own a store, you sell 2 brands, which?

PASS LABS and MAGNEPAN

Both expensive,

I always felt Magnepan was quite reasonable, all things considered.

Luxman and Tannoy

Since I’m happily retired, I would choose PS Audio and Pass Labs.  😏

Can someone explain to me which speakers are not electronic?  Are they things that make sound without the use of any electric input, wires, crossovers, magnets etc?

I've seen pictures of vintage horn like things which somehow physically attach to the source of vibration.

Can someone explain to me why speakers are not electronic?

@noske

Make Wikipedia your friend:

 [Electronics use] active devices to control electron flow by amplification and rectification, which distinguishes it from classical electrical engineering which uses passive effects such as resistance, capacitance and inductance to control current flow.


https://en.wikipedia.org/wiki/Electronics

So  unless you have powered speakers, they are not electronic. :)