I don't think any Palladium speaker parts were shared with any other speaker brand.
I remember the woofers were custom made by Rohacell. B&W also uses Rohacell.
A receiver is just a processor and an amp in one. Some call a processor a pre-amp. Those two items are called separates. You can upgrade your pre-amp and still use the amp, or vice versa. Separates usually sound better than a receiver.
Maybe taking advantage of the current insane prices on rare items. I doubt he needs the money also.
Lots of artist lately selling their entire music catalog, Springsteen sold his for 500m a few years ago.