I don’t know much about McIntosh, other than their more fabled valve designs and their ‘iconic’ blue lighting and meters. It all looks v expensive now. By contrast I’ve owned Sonus fabers since 1997, and followed them closely.
As you know, in the UK, Absolute Sounds imported Sf from their earliest days as an independent. They never handled Mc, and it wasn’t a big brand here, whereas Krell and Audio Research were also imported by AS and often powered Sf at shows and in dealers. With that perspective I never thought Mc was a great match for Sf as both veered more towards a richer/warmer balance - but then Sf became more commercial after Franco Serblin left and started up his own brand (which happily survives his death).
Arguably the heritage moved with the founder, whereas McHifi as you call it became more a luxury good than purist Hifi. Sure enough, wireless devices and headphones appeared, but so did extraordinary top end designs, keeping the flame alight. A fairly disastrous venture into Chinese manufacturing with the pleasant but unexciting Venere range didn’t last long.
My Guarneri Memento are probably the last Serblin influenced Sf design, and they are lovely things, not least to look at! Sadly, globalisation seems inevitable for survival, and Naim at least has gone that way with Focal. Likewise KEF and B&W have been through various owners, and IAG have absorbed many famous British brands.
Being naturally positive in outlook I think that longterm it’s probably all for the good, as nothing can stay unchanged. Time will doubtless tell!