I've been looking all over for a definitive answer but can't seem to find one. Opinions?
It's actually quite the contrary to sounding ridiculous. Many people would disagree with you-but there are two sides to that coin.
No. Some oil based perfumes you pretty much HAVE to rub in.
As for traditional alcohol based perfumes(from the western perspective that is), all it does IMO is gets rid of the volatile top notes.
If this involves that silly myth that rubbing destroys molecules, that is not true.
I don't see how rubbing could damage the scent, and I've never heard an explanation for how it could happen that makes any sense. The scent molecules breaking apart? No. Any scent that is composed of molecules so fragile that they decompose with a little friction would have decomposed long before you spray it on your skin.
Rubbing creates a bit of heat which may help the scent to evaporate and project more. That might affect the balance of the scent slightly or reduce longevity, but it won't damage the fragrant components such that they don't smell right anymore.
Having said that, I don't rub because I'd rather let it evaporate at a slower rate.
I don't think you can generalize about temperatures that fragrance breaks down. Most scents are composed of dozens if not hundreds of aromachemicals, and each will start to break down at a significant rate at a different temperature. I would guess that the manufacturers have studied each extensively and have detailed specifications for each synthetic. Naturals are combinations of hundreds of molecules, so they will vary.
I guess that perfume components are chosen such that they have a reasonable life at room temperatures and normal light exposure levels. Go beyond that, and all bets are off.
I think that light is a bigger problem. I buy a lot of vintage, and what I find is that if a bottle of perfume has been stored in its box, it is almost always good, regardless of how old it is. Topnotes may suffer if the jus is more than 30 years old, but it will still be wearable. If a 30+ year old bottle is bought without a box, it's almost always crap.
The only reason I can think of is that some people spray a wrist and then rub it inside the opposite elbow and then repeat on the other side. I just spray each forearm and let it air dry.