Bold of them to assume that Apple will follow their own guidelines if they are detrimental to their product strategy.
Objectively speaking, these are guidelines, so they are not enforceable the same way App Store rules are. But there's also a lot to say about the differences between Apple as a platform and a Apple as a product.
I think Apple has never even remotely consider the idea of setting the sames rules for their third-party ecosystem and their own products. They have build billionaire business lines on the sole idea of products that integrate better with MacOS and iOS (Safari, Maps, Mail, etc) Anyone who uses an Apple product knows this. So I think is pointless to call them out on that. This has been Apple's playbook for the last 20 years and it will be for years to come unless regulation catches up to them. Time will tell.