Their so-called dedication to privacy is nothing more than smoke and mirrors & feel-good marketing-speak
Not exactly.
Apple, Alphabet and Amazon have a vested interest in NOT selling your data.
The interest in not selling your data comes from selling their own products and services.
Facebook and other social media companies have a business model that includes selling your data.
You are the product.
With Apple, Alphabet and Amazon, they have products and services they want to you to buy.
Selling your data would be but a small drop in the bucket of their overall revenue. They can afford, not to sell your data; at least for now.