This aint new Nick - think Panasonic making (some) Leica digital cameras…and allowing Panasonic cameras to brandish the Leica name on their lens. Similar relationship in the world of cars with Daewoo making cars for Holden, Sssangyong and Mercedes, etc., tis the way of the world I'm afraid.
With all due respect neither of the examples you've given are the same as what I was saying which one of the premium brands in a given item allowing a massively cheaper item to be made (almost certainly NOT by them) - and to wear it's brand openly.
Your first example, Pana/Leica - which I'm not familiar with either reads like a licensing arrangement - Pana pay a royalty to Leica, maybe get some technical assistance - have Leica branding on the lens. I believe Sony did the same with another German lens maker (Schneider IIRC).
Whilst I agree that this does likely somewhat undermine the Leica brand (something Leica would have been 100% aware of but they essentially decided the royalty/extra revenues were worth this) however from what you're saying it's clearly a Pana camera which incorporates a Leica branded lens.
Your second example is again completely different as thats merely a multi-national with many sub-brands and manufacturing facilities, specifically GM in your example - reducing their costs by centralising manufacturing/design etc of certain models and then distributing them under their regional brands in other countries. So GM owns Daewoo and Holden plus many others, but as far as I know L'Occitane and Plisson are completely separate entities.
The key fact I'd use to support my point is that the EARLY L'Occitane-Plisson brushes were ONLY branded with Plisson branding on them- they had no branding on the brushes themselves stating L'Occitance origins. But then this was changed and they became co-branded with L'Occitane and Plisson being equally prominent. Plisson IMHO obviously got feedback from distributors of their own products or consumers etc and decided they needed to differentiate these two....hence the change from this:
To this:
OT for a mo. I think this happens all the time. A one-time exclusive brand like Louis Vuitton now sell all manner of tacky, hugely overpriced shit. The ridiculously expensive stuff the super rich buy for luggage is made to exacting standards, but with many 'affordable' products they clearly aimed for something that has become coined massclusivity.
Again with all due respect, this is very different - thats just bringing in a whole bunch of slightly lesser priced product lines to increase overall revenues. And having just looked at the LV Australia website I'm really unsure what there is vaguely affordable or compromising their core.
When you see LV selling in Target or BigW then I'll agree completely.
Most of the horrid tacky LV items I've seen are clearly unlicenced knockoffs - as they're one of the most counterfeited brands.