I would agree that many OEMs would similarly describe their severe use as such. In fact, my wife's driving patterns fit neatly into all those criteria (the heat, the cold, the short trips and the idling). Which would push me into 3k mile OEM OCIs per the owner's manual. Being a 1995 vehicle, that warranty LONG ago expired, so I'm not concerned about that portion of the equation.
The OEM OCIs hold no interest in the owner; they are predicated on shorter terms of exposure to protect the warrantor (the OEM). Even if something is mildly wrong (a leaking injector, an air leak, etc) the short OEM OCIs keep the wear down low enough that they can get through the warranty period with no issues. They are fail-safe limits that have no bearing on a healthy engine; they are set such that even if something is wrong, it will be flushed away before it becomes too destructive. So, in an effort to protect the warrantor (not the warrantee), the OEM OCIs are VERY conservative. They don't care how much you spend on oil changes; it does not come out of their pocket. It's easy for them to tell you to OCI often when they don't pay of it. You are actually paying excessive money to protect their warranty claims rate. And after warranty expires, there really is ZERO reason to stick with such a pattern when you have data to tell you otherwise.
I do understand that compliance with OEM OCIs is a necessity to have reasonable expectation of warranty coverage. I, too, do the same thing. But once warranty expires, the world is your oyster; there is no reason not to expand your mind, and your OCI.
And that is what most folks here at BITOG seem to miss. They often pay big money for syntethic fluids, then run them at OEM OCIs, and then pay additional money for a UOA, and yet they do nothing with the premium products but waste them. When a UOA clearly proves a healthy engine/lube relationship, why not extend the OCI? OEM OCIs exist in the absence of UOA data. But if you pay for the data, why ignore it?