Let me guess: you played against a full AD team.
And had a ridiculously good ADC in your lane to feed you assists.
And your opponents didn't think to just ignore you because you spent half the early-game as a Taric with nothing but Warden's Mail and/or Glacial Shroud.
EDIT: Yeah, just looked up your most recent Taric game on LoLking; in a 29-minute game you had 23 ASSISTS and yet you still only managed to finish Randuin's, Thornmail, and Ninja Tabi (with enchant apparently). That's the thing - the item loadout you suggest, while it would be pretty sick to tank towers with (and honestly it would be pretty tough to kill you for non-AP champs), costs a RIDICULOUS amount of gold for someone in a support role, especially considering that you apparently skip gold items...?
In a massive, long game where everyone gets six items it MIGHT make some sense to get that build on Taric. In my mind, it still doesn't have enough MR for all comps, and it has no tenacity whatsoever - if you try to engage, you'll walk in and just get CC'd, then murdered from a safe range with magic damaging abilities.