Contextually there's nothing wrong with walled gardens. It's like regulating the apps I put on my smart TV -- literally no one cares, nor is my TV holding a market leadership position, nor is it a sales entity in its own right, nor is it going against standards, nor is it.... etc.
And even though those names are huge, you have to respect the "gatekeeper" label. Sony isn't designing a phone that has 20% of the market with proprietary cables, a closed and insular app store, a closed and insular payment process, etc. Show me an example of Sony or Meta performing the same behaviors. It's not about how large the company is, it's about how it plays equally in the field as a gatekeeper to other products in the field.