I would assume that you woudln't be forced to buy your name if you own the trademark because within-reason nobody else would be able to buy it.

True, but let's say I start an apple reseller and want store.apple. That would be just fine on all counts; should Apple Computer have every instance of the word "Apple" reserved for them just because they're bigger? It would frankly be irresponsible for some companies not to: as consumers get used to esoteric TLDs, it could become a phishing concern.

Doesn't that apply only if the other company is a competitor to you? E.g. a shoemaker named Microsoft could get the domain if it was clear they're using the name fairly.

Yeah, I could see a gTLD version of http://nissan.com/

The bar is very different though. A local business is unlikely to be approved, even if their name wouldn't confuse people.