Which is quite logic because historically:....
The 2E AD&D PHB shaped my conception of D&D, even though I didn't play it much. I found it interesting that it specifically mentioned the Knights Templar were listed as inspirations for the Cleric, not the Paladin. And the 2E DMG mentioned that Paladins are too rare for organisations to exist bigger than the Knights of the Round table.
Knight Templar were not necessarily Lawful good, they often did consist of second or third sons because only the firstborn noble would inherit. They were obviously also a strong financial organization with materialistic goals which is diametral to a classic paladin.
It is questionable if they even had some heretic beliefs, be it from advanced knowledge or to form a stronger bond of "initiated", so they would eventually go along not so well with official church.
From 2e game mechanic:
Rolling attributes was the standard method. Even if you used systems different to 6x3d6 in a row the minimum scores needed for a paladin were quite rare to achieve. I do not recall the absolute probability but it was less than 1 in 100 chance or so depending on rolling method.
The knight Templars were a big organization, certainly more than paladinsavailable in a equivalent game world.
Round table is an excellent example for paladins. Their quests were really for idealism and to honor chivalric code.
edit: Uups someone resurrected this nevertheless quite interesting thread a few pages before my post.