A new tire tread will typically have 10/32 of an inch of tread, and some expensive tires may have 12/32 of an inch. So, 7/32 is pretty good, but is not comparable to a new tire.
As you have probably surmised, tread wear varies considerably from one model of tire to another, and the tires that come on most new cars are not noted for very good tread wear. Good quality replacement tires that are selected for long tread wear may last 3 times as long as the ones that new cars come equipped with.
The sidewall of all tires sold in the US will have “scores” for tread wear molded into the rubber. A “new car” tire may have a tread wear rating as low as 150, and good quality replacement tires may have a tread wear rating of 600 in some cases. You get what you pay for, generally speaking.
However, these tread wear numbers can only be accurately compared within one manufacturer’s model line. In other words, a Goodyear tire with a tread wear rating of…let’s say…300 will not necessarily have the same tread life as a Michelin tire with a 300 tread wear rating. The tread wear ratings are accurate only when comparing the same manufacturer’s tires of different models.