How were watches / bracelet / strap combinations originally sold?

Hoping someone can provide some insight. Many vintage watches which come on to the market via estate sales etc. seem to have aftermarket stretch bracelets or leather bands. I'd imagine original leather is unlikely to last fifty-odd years, but why do you see so few factory bracelets?
I'm curious to know how Omega (or other brands) sold their watches back in the 50's, 60's, and 70's. Were watches sent from the factory with a particular bracelet or band, or would they arrive at an AD and be fitted with the dealer's or customer's choice of what was available, either matching factory parts, or aftermarket? I'm sure there are combinations of these and other scenarios, but what was the norm?

No comments? If anyone is able to help with this I'd appreciate it.

I think the norm was, buy the model you see on display or not, however you could and you can still buy bracelets for a model, whether it came without one or the bracelet was worn - you could also ask for special things but I believe people rarely did, as there are very few special models that could only be special requests

I followed this as I was curious too, shame it got no replies yet, here are my third hand / market based observations:

1) Leather can survive 50 years if unworn and kept well
2) Factory bracelets survive and a lot survived
3) There were options like today, some models were mostly bundled with their bracelets
4) Sometimes you see something that is wrong in 10's of examples, maybe Omega didn't care about correctness as much, or these mistakes happened in parallel through AD's or wearers in parallel globally - as an example, an endlink/bracelet combo that fits by fitment only and not out of the box, or a buckle that's for another model or another time appear on models it wasn't supposed to appear on, maybe someone who bought a watch went to an AD 5-6 years later, and got such a bracelet/buckle, and now it's part of the observed original options

For this reason I'm always curious for replies, never heard of a first hand experience, or a passed down information

Sellers get more if they sell bracelets and watch heads separately. I suspect this may be why you often see good watches sold on cheap aftermarket bracelets or straps.

Interesting. Thank you. I assume, based on the pictures, a majority of watches were sold with a leather band originally. Few seem to have bracelets shown in the adverts. Would it be safe to assume a factory stainless steel bracelet would be an fairly expensive upgrade that a few people took, but not that common? Probably an expanding metal bracelet would be a more common alternative, certainly to replace the original band when needed, but also as an option from new. I think this would account for the quantity of expanding bracelets seen, as well as the relative scarcity of factory bracelets.

Are you saying you suspect many were sold with Omega branded bracelets, or just some mixture of aftermarket and Omega?