The LS motors from 2003 on use valve overlap for EGR when they went to drive by wire. There isn't any extra hardware anymore. You still have some degree of EGR, it's just built into the engine structure. I'm sure there are other things that go into it as well with the drive-by-wire throttle.
I'm young enough to understand the oil life monitor ideals, but old enough to reme dojng 3k services all the time in the shop business. 5k became more comlon with good syntht oils. All automakers strive to make the cost per mile of ownership as low for the end user as a sales pitch. Hence super long intervals on all fluids, etc.
Certain engines seem to deal with extended drain intervals better than others. Take the 3.6 in most GM cars - go by the oil life monitor and get the joy of putting a timing chain and tensioner in just after the warranty expires. OR, change it more frequently and not have that issue.
Oil is cheap in the big scheme of things, so do it on the 5's and have an easy way to remember when it's due next.
The only time I would consider 7500 miles is if I were an over the road driver and did all interstate driving for long periods each day. Cold starts, and stop/go driving makes the oil dirtier much faster.
Case in point: drove my 2008 denali from WI to NM, CO and back. Oil still looked brand new when I returned because of the type of driving. Added about 2000 miles of normal driving afterwards and it dirtied up pretty quickly. Just my 2 cents.
