^^^^^^this, mostly. There's alot of factoring that goes into the end design, build cost, brand image, reliability, service intervals, owner maintanence, owner abuse, QC, etc.
The goal is to provide a car that offers competive features in It's class at a competitive cost and last ATLEAST as long as the warranty period and is as cheap as possible to manufacture.
If the goal is a 100k mi of trouble free driving then they must build the car to last for substantially more miles, like say 150k mi. Why? Short answer BELLCURVE STATISTICS, then most cars will last that long without much fanfare and the failures before warranty will be a small percentage (conversely so will the ones that last longer without issue, BC Bellaire).
That said being more vigilant about preventive maintenance than the manufacturers recommende is not a bad idea. They're using the cheapest fluids that meet the minimum requirements and recommending the longest intervals possible (because of improvements in fluids, ease of maintenance, waste reduction, and largely lazy a$$ owners). Using higher quality oil leaves you more margin of error for adequate lubrication (among many other things) while using long OCI's.
Also having worked in production machining I can safely say that contaminants are greatest during early operation as debris that has not been removed during the wash and early parts testing is dislodged and circulated thru the engine (and keep in mind the filter isn't always its 1st stop!). Also as parts are breaking in and that can add further debris and release filings that weren't removed during deburr, wash, fluid cleansing, testing, etc (they do go to great lengths to minimize this thou).
So yes doing the 1st oil change is a decent idea. It probably won't make or break the long term longevity of the engine, but it might make a difference and it certainly won't hurt it. Having worked as a tech for several years and doing production machining and washing of parts I think going 7-10k miles on the factory oil is negligent.