What proprietary standards do you mean? Web technologies aren't proprietary.
Oh, and make it work flawlessly across every site (including the top 10,000 alexa sites) without any issues at all. And try and wade through the mountains of chroumium exclusive bullshit (Google makes the standards).
Go talk to Mozilla about how easy that is (they even have to spoof UA strings to make things work properly).
Good luck.
https://developer.mozilla.org/en-US/docs/Plugins/Flash_to_HT...
Some content creators protect their's content more some less. What has that to do with open web?
If you don't like Facebook/Youtube/Reddit censorship(moderation), you are free not to use them (they are private platform).
If you don't like installing proprietary blobs to watch Netflix, you are free not to use Netflix (they are a private company).
If you don't like paying taxes / agree with government, you are free to not live here and move to Somalia (this is voluntary society and you choose to pay taxes!).
I'm sure there are few other similar ones, just can't recall them at the moment.
Some content creators protect how their websites look more, some less. Would you still consider CSS a part of the open web?