I think that's silly. Another one of those..."The Star Trek fans are too stupid or too demanding to accept changes.." moments.
According to Richard Arnold's annual convention presentations of day, uniform changes are also pushed by the licensees. Playmates Toys had done tens and tens of action figures by the time of "Generations" and had won the new tender to do tie-ins for the movie. If Paramount had used the same design as the TNG series uniforms for "Generations", the only all-new figures that collectors would cherrypick from the set would have been the two Klingon women, Soren, Kirk, Chekov and Scotty, plus Worf in holodeck outfit and Kirk in orbital diving suit, leaving the key seven 24th century Starfleet characters of Picard, Riker, Data, et al hanging on the pegs.
When a uniform push is not enough, or not successful, the action figures undergo a change of scale. For "First Contact", of course, Playmates did both.