No chance.. United's treble eclipses the invincibles.. they were impressive and dominant, but a world class powerful team who came up short in Europe. Fergies Aberdeen were minnows.. even in Scotland.
3 European cups.. impressive.. but as you say its about who you play.. in those days you only had to play the champions of Spain, Italy, Germany.. the rest were minnows.. OK many of the other nations in the east were stronger, Red Star etc, but most weren't.. despite the moaning the CL is a much higher standard overall than the EC..
Still it was bloody impressive, but it was basically one team.. one club, Fergie remained at the top from almost day 1 and evolved with the game as it changed more than ever before.