If owners are going to develop their own practices with respect to care, operation and maintenance of aircraft, why do people like me go to all the effort to write flight manual supplements, and instructions for continued airworthiness for these aircraft?
I tend to agree but I think there are additional factors:
Lyco/Conti are under immense legal pressure to not change their operating recommendations, irrespective of how much "history" has passed by outside their dusted up windows. This is because many of their engines fail before TBO when they are put together right, and many more fail before TBO because they are not put together right. So they work hard to evade liabilities, and modifying their operating suggestions would be an admission they originally "got it wrong". Hence all the garbage they continue to write re LOP etc. This is probably why they say -12C (or whatever) without qualifying it according to oil type used, which makes the -12C (or whatever) an obvious farce if stated as a straight unconditional figure for a given engine type.
For each type of oil there will be a low temperature below which it doesn't flow well enough to get around a (particular design of) engine fast enough, before it gets a chance to warm up. This behaviour should have been studied (they have been making these things since the 1950s, essentially) and documented, but nothing has been done. It is possible there are owners out there who regularly start at low temps and regularly get trashed engines, but I have not heard of it. Maybe they all preheat, or maybe the problem is not as big as it appears, or is much more engine type specific.
The lowest I have started mine at was probably about -3C, and the oil pressure gauge was up in the green within a few seconds; same as it always is. I don't know (without looking in the engine MM) how far along the oil path that gauge comes off, but it is supposed to be right at the end, for obvious safety reasons. This kind of stuff should have been documented by now.
It is the arrogant unwillingness of the manufacturers to get stuck into some proper research and documentation (and I fully understand why they behave like this - the above legal reasons) which has given rise to countless theories on engine management. Deakin (etc) would have not had anything to say if Lyco/Conti did some proper bench research and were open about the results.