I think for me, I would pick a manufacturer who is doing cool and innovative things. I don't mean they do great in the market, but that something unique is happening.
So, anyone with their own CNC machines, like Magico or YG would probably interest me. Early days of theater sound, so JBL and Altec Lansing.
Working with Snell and his curved baffled in the A models. Genesis with the line arrays. Apogee making giant magnets and ribbons. Not a maker, but I wish I had actually gotten a degree at GA Tech and been able to do graduate studies with Dr. Leach. Maybe Jensen transformers, and whoever was making the earliest op amps in tin cans.
Best,
E