There's a lot of terminal draw and cards that don't draw for you in the deck. Even with Ironmongers and Stables, you can't really expect to go through the whole deck playing all of your terminals each turn without some very fortunate draws. Knights especially also tend to slow the game down; mainly they hurt the opponent, but provide very little benefit to you. And there's not much wrong with that here, since you were playing Knights often enough to significantly slow your opponent's progress (especially since he was trashing down so your Knights could consistently hit targets).
I'm a bit surprised he didn't go Mountebank here. Guess he figured Hermit and Stables were enough to ignore it, but trashing down makes you so vulnerable to Knights...I'd probably get Mountebank anyway since Hermit can't trash the coppers, prioritize Stables and Ironmongers, definitely get a Black market, transition to Knights if he contests them or if he trashes down, or if there's a really good Knight on top (Sir Michael and Mountebank are really good in tandem). I don't expect it to go quickly; when Knights are significant, it can become a war of attrition.
