@vitussl101 -Amen. Not all old equipment qualifies. And the brand name Marantz became a different story once Saul Marantz sold to Sony/Superscope.
I still have my Quad 57s from 1974 that were sympathetically restored by Electrostatic Solutions and a pair of Quad IIs with period glass that Bill Thalmann went over - he said he hadn’t seen real GEC KT66s in a long while. That stuff is enduring, though it still has limitations.
I had a set of Crosby Quad 63s which I basically gave away when I moved-- I preferred the original Quad loudspeaker to the 63, even though the latter is a better "all-arounder."
Some of this gear enters collector’s territory, eg. the Marantz 7 tube preamp. The "C" is for cabinet, does not necessarily mean it is a tube unit. Lots of those were around back in the day, some were modded. At the time, I preferred the ARC SP3-a-1, which is now itself an antique collectible. But your point- that "older" Marantz doesn’t equate with quality sound is a fair one.