False. They have more in common with each other, both in their mechanics and their methodology, then any of them do with 3E and beyond. Your statement is simply factually incorrect and there's no reason to wrangle over it.
Depends on what you mean by both "mechanics" and "methodology"
For example: Take alignment. Classic OD&D had three (Chaos, Law, Neutrality) which continued through all iterations of the Basic game. The Holmes "Blue Cover" book had five alignments (CG, LG, N, CE, LE) which closely mimic the spirit of the five alignments in 4e. It was AD&D (1e, 2e) and third edition that had the classic nine (LG, NG, CG, LN, N, CN, LE, NE, CE).
By the "mechanics and methodology" of alignment, the games that "beget" others follow.
OD&D -> B/X -> BECMI -> Rules Cyclopedia
Holmes -> Fourth Edition
AD&D 1e -> 2e -> 3e -> 3.5
See how easy it is to lump games together when you define the criteria?
I could, also, use ability score mods, lumping the ones that give a simple bonus vs. those who have complex multiple bonuses (which would lump OD&D, Basic, 3e and 4e together while excluding AD&D). Or which editions allowed multi-classing (all but Basic & OD&D). Or editions where Fireball is a d6/level (all but fourth). Need I go on?
See, Old school players need to define a criteria that allows OD&D, B/X, Holmes and AD&D to be "old school" while ignoring or revoking BECMI, 2e, 3e, and 4e from the mix. So far, that criteria is "games made before 1985".
Unless you can point me to more...