Which just shows how little you know about pool. NOBODY, in any game, makes a ball on the break anywhere near those numbers, EVER.
Did you mean "with a wooden rack"?
Because once you have a magic rack, they absolutely can.
World 9 ball -
2014: The breaker made at least one ball (and did not break illegally or foul) 89% of the time (226 of 255), won 61% of the games (155 of 255), and broke and ran 35% of the games (89 of 255).
2015: The breaker made at least one ball (and did not break illegally or foul) 88% of the time (300 of 340), won 62% of the games (210 of 340), and broke and ran 37% of the games (126 of 340).
Something close to these numbers can probably be put up without a template, if it's a really good triangle (delta 13), a competent racker, and a table that doesn't have divots.
50% reflects the average for a full field of top pros, average pros, and donators.
With good gear and top-50 level players, I'd predict at least 75% with a triangle, if breaking from the side rail is allowed.