Yes, they argued they want to set a standard for mechanical design sooner than later as they plan to place the display further to the edge.

Half of that is definitely not true. I do believe that we'd have to move away from the 0.14in/3.5mm headphone sockets as mobile become thinner and thinner, but there is no need to implement this beforehand.

As such, the reason Google followed up with the same scheme as Apple, was to prevent them of monopolizing the market. Since Apple's Bluetooth headphones would work with Google's products, people might walk around with a mix of Apple and Google.

Removing the socket forces users to become aware of their own product and drive the third-party market to further limit Apple's influence.