Earlier quoted context omitted.
This is a nice conspiracy theory but doesn't match facts like Safari implementing the WebGPU standard at a faster pace than Firefox. Safari might not be great in some areas, but their WASM/WebGPU/WebAudio support is in pretty good shape.
Push Notifications, Web Bluetooth, Web NFC, User Idle Detection, the list goes on and on. Not even counting the hundreds of #wontfix bugs in their css engine. Its not a conspiracy theory if you recognize their incentives and consistent anti-consumer behavior for fucking decades.
These are things that literally everyone but Google thinks are terrible ideas.
Why don't you flip the conspiracy around and ask yourself why Google, the world's largest advertising agency and data hoover, wants browsers, a category dominated by Google, to have unmediated access to ever more user, system, and local network data?