>>Bodaci+(OP)
It's incredible, most of these are large companies (Zoom, YouTube!) or government entities. They should just be able to send an email (or a registered mail on company letterhead) saying "Hello, we are Google, your website is broken. Please make the following changes.". Fixing sites for other people is less work and technical debt than adding it permanently to the source code of the browser.
And if it is not bugfixes, but keeping around features that were removed: if youtube.com uses something, why can't everybody else use it?