Barrel quality can have some effect on accuracy life but most of todays factory stainless steel barrels are pretty damn good as far as barrel life goes.
A loose throat will effect accuracy life more then anything simply because they allow more gas blowby around the bullet before it seals the bore. This causes an flame cutting effect on the throat. THis is generally why a match grade barrel will have a longer barrel life, because they are usually chambered with a much tighter, match grade throat which dramatically reduces this gas blowby.
For example, some factory throats will have a throat 1 to 1.5 thou over sized compared to bullet diameter. This may not seem like much but when talking throat clearances, ITS ALOT. Most of my throats on my custom designed reamers will have a neck diameter of 0.0002 to 0.0005" over bullet diameter so they are DRAMATICALLY tighter then any factory throat.
There are some match barrels that will tend to offer longer accurcy life with these high intenstity magnums but how you care for the barrel by keeping it from getting to hot while shooting and keeping it clean will effect barrel life much longer then anything else.
To that end, if you heat up a 7mm RUM or even a 7mm WSM
for that matter and keep shooting it, they will have a shorter barrel life then even a very extreme 7mm AM that is used properly.