Honda does officially state that the owner should keep the factory fill according to normal OCI (7,500 miles) at the Break-in section in owner’s manual. And Honda also said many times they use high-moly break-in oil in factory fill. As for Mazda, the owner’s manual says they use Mazda genuine oil, and the UOA indicates the factory fill from CX-5 has very high content (~650) of molybdenum which is similar to Mazda moly 0W-20 oil.
I'm fully aware of what you're pointing out. As I said, there is nothing wrong with keeping the factory fill in for the full initial OCI. But if you want a more nuanced discussion about this.....
The high moly in UOA's of factory fills is more/less universal across all makes. Multiple technical sources attribute it to the high-moly content in assembly lubes that are used heavily in car engine building and which get mixed into the factory oil fill on initial startup, not a special oil. And I repeat what I said earlier - 95% (probably a conservative number) of engine break-in wear has occurred in 2K miles, so continuing to use a high-moly oil for the full normal OCI will have negligible effect on break-in. Conversely, getting the relatively contaminated break-in oil out of the engine and replacing it with clean/fresh oil for the remainder of the first OCI MIGHT be beneficial.
Why does Honda admonish owners not to change the oil early? It's probably because their experience is that owners are very aggravated by having to bring in a car to the dealer after owning it for a few weeks - compared to other makes, it makes the vehicle appear to be "high maintenance". If keeping the break-in oil in an engine out to the full normal OCI results in "acceptable service life" out of an engine, then acceptable is good enough even if there is some benefit to an earlier oil change. And the expense of early oil changes to rental car fleets and commercial service would be onerous. So good enough is good enough. But that doesn't mean it is optimal.
Another aspect might be warranty expense. Two weeks into car ownership, a new owner is hyper-sensitive to how the car behaves and if they have to come in for an early oil change, they have a list of ten things they are worried "might be wrong" and want checked out. Six-months later, they will have learned that many of these things are normal and are of no concern. Instant dramatic reduction in warranty expenses.
If you want to apply the service recommendations of one vehicle type/make to others, I can point out that nearly all motorcycle manufacturers still REQUIRE a 600-mile oil change to keep the engine warranty in place on a new motorcycle. So at least in in motorcycle service, there is a strong benefit to getting the break-in oil out of the engine early on and replacing it with clean oil.
This is just my reading of the tea leaves - that an early 2K OCI won't do any harm and MIGHT do some good. But I would never say that is is necessary/required, or even very important.
- Mark