Hussar
Legend
Perhaps but they were still optional we rarely used psionics for example. 3.x and 4E are the odd ones out in terms of optional rules.
Odd or simply recognising how the game was being played? I'm not really convinced that labelling these things "optional" in earlier editions meant a whole lot. To be fair, 3e did label a number of mechanics optional, such as random AC's in the DMG, which, because they were optional, were never used too widely. OTOH, something like Action Points, while purely optional, seemed to show up pretty commonly IME. So, I guess it depends on the rule.