Apple was the exception because they initially went with AT&T. Jobs demanded no carrier interference. The first carrier they approached (Verizon, IIRC?) refused Jobs' demand, so instead of caving, Jobs went with another carrier.
It's an eerie feeling finding errors or omissions in what is commonly used as an irrefutable source of truth in the modern world. I appreciate the correction though!
Perhaps irrefutable is too strong a word, but if I'm looking for an answer (instead of researching a topic) and want a quick, single source, Wikipedia is my go-to.