The closed aspect directly speaks to how much diversity you can have on the platform. The features (like WebUSB) aren't the drivers for a more open platform, but they highlight what the impact of having no competition does. Opening up the platform will fuel competition and the market can decide what works and what doesn't. At the moment, we just have to trust Apple has our best intentions by supporting/not supporting certain features and standards. However, we know from the work the Open Web Advocacy has done that this isn't true. The primary driver for both stifling progress on Safari and keeping browser competition out is the profits from the App Store [2].
Chrome becoming the dominant browser is also concerning, and they will have to be held to a much higher scrutiny by us and policy makers to ensure they have users best interest at heart [3].
> shifting the cost of compatibility into userland
What do you mean by this?
> struggling to pay for their last-minute plane ticket at the gate but being greeted with "Sorry, our checkout page doesn't work on your browser/device". This is not the way.
I agree! This is exactly why we can't depend on one organization to dictate what's allowed and disallowed on that platform. On iOS, think about how long it took Apple enabled Apple Pay support for non-safari browsers even though they all had to be WebKit-based.
[3] https://open-web-advocacy.org/walled-gardens-report/#the-chr...