Marantz is solidly mid-end. B&W is a wide range from mid end to high but no high in the gear that is at Best Buy. High end is never allowed to be sold in chains or online.
High end also never has things like center channels, receivers, etc. HiFi means the pursuit of sound alone is the goal. Everything here is still focused on convenience.
Speakers from Wilson, Totem, etc. nothing anyone outside of the audiophile space would have ever heard of. Amps from Conrad Johnson, Meridian, etc.
Real HiFi used separates. Amps, preamps, etc. tubes aren't uncommon. Wiring is a big deal. Etc.
It is hardcore stuff. Makes no sense for normal people to own. If you don't design the house around the acoustics you should never invest in that stuff as it is wasted in a small or untreated space.