By the way, this is as old as web. It's ironic to re-read https://dev.opera.com/blog/opera-s-site-patching/ published in 2009, which uses 2022(!) as a stand-in year for far future when hopefully none of this will be required.
>>sanxiy+(OP)
The bitter irony is that it was indeed "solved" - not by HTML5 as (the original) Opera dev team implied, but by Chromium being in a ~90% market share.