How will they maintain their jewelry business ? It feels like Sony CD-R drives in the Playstation era.
The same way rolls royce no longer sells luxury cars to stuffy British aristocracy but makes a mint building huge jet engines.
RR cars has been a BMW subsidiary for 21 years, having been separated out from the aircraft engine manufacturing business in the 1970s
https://en.wikipedia.org/wiki/Rolls-Royce_Motor_Cars
https://en.wikipedia.org/wiki/Rolls-Royce_Holdings
(unless that's exactly what you meant of course, Rolls Royce Holdings indeed no longer makes the cars... )
Tiffany's isn't suddenly going to be cheaper.
DeBeers are just positioning on price, natural more traditional and romantic, etc.
Who wants to know their engagement ring was half price?
I mean...a ton of people. My fiancee and I just purchased her ring together and it was pretty much a silent agreement from both sides that lab grown was the way to go (confirmed out loud of course). The stone we ended up getting was about 1/10 the cost the closest natural we could find, and both of us agreed that there are way better ways to spend that money with everything else in the future.
Many people also love jewelry but would rather not have something worth a brand new car on their hand.