I'll go through that list of the chanceless "small" (say, 100-140) centuries and see in which ones you can say "should have gone on".
OK, finally got around to this...
Strauss V Australia 106: second-innings, trying to set a total and declare - no blame there.
Flintoff V Australia 102: could have gone on, but TBH this was one of very few truly convincing innings this game, and I'd not apply too much blame there.
Strauss V Australia 129: yes, should have gone on really. Proved enough ITE - but only just.
Collingwood V India 134*: not-out, obviously no blame there.
Pietersen V Sri Lanka 142: was "big" enough for my money, and was easily the difference between the sides.
Bell V Pakistan 100*: not-out.
Strauss V Pakistan 128: second-innings, trying to set a total and declare - no blame there.
Cook V Pakistan 127: big enough really, England cantered this game.
Bell V Pakistan 106*: not-out.
Bell V Pakistan 119: big enough, was batting with the lower-order in part too.
Collingwood V Australia 206: easily big enough, double-century. Still lost tho of course.
Pietersen V Australia 158: same team-innings, same story as Collingwood's above.
Cook V Australia 116: not enough, sadly - there would've been hope going into the last day if he'd stayed there. Always fairly reluctant to criticise too much tho as most at his age (21) would never have been close to being up to scoring even 116.
Cook V West Indies 105: should have scored more, but the fact he didn't wasn't ever likely to matter.
Bell V West Indies 109*: not-out.
Prior V West Indies 126*: not-out.
Pietersen V West Indies 109: second-innings, trying to set a total and declare - no blame there.
Vaughan V West Indies 103: could and certainly should have gone on - there was something massive on a plate for him. Not that it mattered to the game of course.
Collingwood V West Indies 128: should have scored more, but the fact he didn't wasn't ever likely to matter.
Pietersen V India 134: second-innings, trying to set a total and declare - no blame there.
Vaughan V India 124: exceptionally unfortunate dismissal, can't really blame - and but for that might very well have gone on (and maybe even saved the game) he was batting that well.
Pietersen V India 101: saved the game so good enough.
Ambrose V New Zealand 102: vital, vital contribution to a vital victory in a pretty low-scoring Test.
So as you can see, I don't really think you can attribute a particularly massive amount of blame there really. Certainly hardly any of them where the failure to score very big cost the game. Mind, players from many other countries I'd bet get similar outcomes, and still take those small windows of opportunity that present themselves.