Based on your reasoning, why don't all other automakers (all have large marketing budgets, GM spends even more than Toyota) have similar reps for quality?

Toyota's rep has been well earned, there's plenty of literature in operations about this, as well as popular trade coverage (i.e., http://www.nytimes.com/2013/10/29/automobiles/japanese-autos...)

Their software process wasn't given the same attention, and they've been burned by it. Embedded systems are really tricky, and a good process (design through end-of-life) is key.

It's not just marketing. I was in the manufacturing program of a large public university in Michigan, where you would expect all the staff to be heavily biased in favor of Detroit automakers, and the constant refrain was "Toyota, Toyota, lean manufacturing, six sigma, Toyota."