Yes, pretty knobs matter. The right heft and feel is part of a quality user experience. I bought a bottom-of-the-range new Sony AVR in like 2010, and the experience sucked because too many options were buried behind a complex OSD and menu, while on the equivalent 40-year-old model was a single direct-access button.
You can crush a Harman/Kardon 730 to its component atoms, and there's an enthusiastic community that will help you restore it to operability. Virtually all the parts are available on Mouser or Digi-Key, and many can be replaced with better ones (tighter tolerances, smaller physical sizes) for peanuts. I doubt that new Sony AVR will ever be close to as fixable, let alone 40 years from now.
It's entirely possible that the right new kit will sound better, but I suspect as much as anything I'm room and layout limited more than gear limited. No point getting to -200dB signal to noise when there's a constant AC and CPU fan whine in the backdrop.