Seems to me the old saw of 3-mos/3000 miles is perpetuated for several reasons, including (in no particular order):
1. The car service industry not wanting to let go of a money-making practice.
2. The general conservatism of service technicians in terms of acknowledging new techniques, materials, etc.
3. The industry's probably well-intentioned desire, long ago, to devolop an effective and easy-to-remember slogan that would more than amply cover just about every car owner out there, even the absolute worst in terms of how he or she takes care of their cars. Ample protection for the worst of the worst.
3a: Human nature. Tell someone oil is legitimately good for 6-10K miles and you know people are going to neglect or forget to a point way beyond that. Tell them it's good for 3K miles and when people finally come in at 5K or 6K, they're still well in the safety zone with modern oils.
3b: The disappearance of filling station attendents who used to check your oil. Let's face it, oil issues are not just issues of dirt but issues of leaks and burning, too, which leads to low levels. The industry probably figured "hey, better get most consumers in at 3-mos/3K miles because with no one checking oil levels anymore, that's probably the safest time period."
So, the money-making issue aside, IMO it's mostly a HUGE belt-and-suspenders way of the industry trying to protect consumers against themselves...the lazy, or forgetful, or truly unknowing consumers out there, which I'm guessing members of BITOG are definitely NOT....at least when it comes to their cars!
But look at it this way, guys (and gals). There's many things automotive-related that we don't do anymore like our daddies or grandfathers did....like flush the radiator every year...even though (like frequent oil changes) it could be argued that it's "cheap insurance." And why don't we follow an old practice like that? Well, it's just not necessary anymore. Seems as natural and logical for us NOT to do something like that because componets have changed for the better. So in the very near future, when virtually every car somes with an OLM, and brand new generations of drivers know nothing of oil changing other than doing it when the OLM says it is time, these new drivers will never even think twice about some "old fashioned" practice of 3-mos/3K miles. And they will legitimately wonder about the sanity of anyone who still clings to that practice.
