The funniest bit is that those bespoke systems have one manufacturer, but are just premium branded, just badge engineering.

An excellent example that I’m aware of is PSA (Peugeot and Citroen) where the Hi-Fi option was cobbled together from different parts, like head unit from Magneti Marelli, Bosch or Harman, amplifier from a number of different manufacturers and speakers usually from JBL, all branded as a single Philips (in Germany and sometimes the Netherlands), Denon (in Germany and some other markets) or JBL (default in most markets).

So if you don’t like our don’t appreciate one brand’s credentials as sufficiently Hi-Fi, just get your car in a different market.

Dali, Focal, KEF, and I’m sure plenty other brands make 4-way speakers. They’re typically made by taking a 3-way speaker and adding a subwoofer (like Focal does in Grande Utopia which has 6½ inch midrange, 11 inch midwoofer and a stonking big 16 inch sub), or an ultrasonic tweeter (like Dali does, but they call them 3½-way, also Sony and KEF).

I guess you can make a 5-way by adding both.