And based on the their upstream contributions[1] it doesn’t look like it was a gesture of goodwill.
No, they were forced to release parts of it under the same license. There was a lot of original Apple code that could be separated out easily and released under any license they wanted (or kept proprietary) as long as they released them as object files so could modify and relink in the modified LGPL parts.
The parts that Apple was not required to release under LGPL they released under BSD.
Google used the strong weight of Youtube to make sure all web browsers implemented a replacement, a long and tiresome process that took the better part of ten years. They bought companies and gave patents away along the way.
I'm not sure exactly what Apple did. Please enlighten me.
It definitely wasn't just Apple. Google and Mozilla certainly played a huge role, and I definitely consider them much better web citizens than Apple (Mozilla best of all, obviously), but a lot of sites switched to HTML5 video only because they wanted to be watchable on iOS devices.
Adobe could have struck a deal there, given Apple their 30% and only allowed blessed scripts through the App Store. But they didn't. I would be surprised if there weren't neogiations about this, but in the end Adobe refused.
(Other scripting languages budged, which is why you can find Unity games in the App Store, but not Adobe Flash games. Unity was also banned at the same time Flash was.)
So if anyone kept Adobe Flash off the iPhone, that honor should probably go to Adobe itself.
Apple played a massive part in the success of the mobile web and responsive design. The release of Mobile Safari and WebKit was a watershed moment. Before that point, the mobile web largely consisted of separate, pretty awful sites on WML. Afterwards, most mobile platforms had a default web browser based on WebKit, and the mobile web transformed as a result.
I'm not saying Apple are perfect, but saying that they've "always been awful for the open web" is grossly overstating things.