Those formats are also more logical(ish) than human language, so reverse engineering them should be possible in some cases.
Also, there will be plenty of 'rosetta stones' around: media that exists in both an obsolete format and a more recent, better understood one.
From the 70s-90s most consumer tech was thrown in land fill when people were finished with it. There wasn’t yet much of a “collector” mentality because it wasn’t old enough to be cool, and there was such a mad rush to always have the newest developments in that tech-honeymoon period that people threw the old stuff out.
Then for the software side, storage was expensive and complicated. People didn’t keep copies of every single old thing like lots of people do now, websites were purged of old content to fit new content, versioning in development didn’t really exist (on a large scale).
I’m a retro tech/software collector and there’s plenty of stuff from my childhood that I can’t find a single trace of anymore.
(silicone is not bio-degradable, right?)
So I'm guessing it's also not biodegradable.
Edit:
The 1,500-degree Fahrenheit heat of cremation will burn away all of the body's natural substances, leaving the bones to be ground up
Silicone implants remain behind as a goo, while metal implants, like hip replacements, remain completely intact
https://www.dailymail.co.uk/femail/article-3228354/Mortician...