Again, you can't take aw.org standards and apply them to economic principles.
I have matching sets for oven and induction cooker, washer and dryer and that's it.
Thing is MOST other people DON'T care about having the best everywhere and DO care about saving like 1000€ or $ on a kitchen remodel.
Here in the EU, that's even further to the point certain SKUs are ONLY made available through furniture retailers.
If you move enough volume, you get them cheaper. That's a big thing behind the package rebates, too.
Also, putting a lot of the cost onto the resellers. If a kitchen outlet buys like 500 ovens at once from the same company and gets them shipped to one central distribution hub, that saves production setup costs and distribution costs.
And since the furniture company had to ship all the cabinets anyway, letting them handle final delivery saves money for all partys involved.
When my mum bought her new kitchen, the difference between buying all the appliances with the furniture or just the furniture was only about 2000€.
Even at cheapest retail pricing, buying the appliances extra, that appliance set was 2500€ or more.
Could she have had a slightly better oven and cooker for just a little more? Yes, sure.
Is she perfectly happy with the 5 year warranty she got for free, having everything fitted by the installers and having stil very good appliances?
Very much so.