Amiga did it. We can do it again. Besides, such an API is a slow-moving target, so still better than status quo.

Are we thinking about the same thing? Amiga did not have a perfectly future-proof API. Such an invention would be the holy grail of API design.

Some future proofing is better than none, right?

The status quo is the continued existence of IrfanView, which is probably as close as it gets to the ideal. Hasn't changed much since the 1990s, and looks like it, but supports about everything via plugins.

IrfanView is updated constantly though.

Yes, but the idea is that even if the original author dies, people can still keep using the last release of the application, but independently write new plugins to interpret new image formats that come out in the future.

Winamp has a similar property. If in 2030 FLAC is replaced by some fancy neural-network based lossless encoder, it can still read the files and play them without touching the core of the application, because all that's needed is a single plugin.

Well IrfanView is open source, so if the original author dies I would expect someone else to pick it up.

Your description might help with one specific area (compression algorithms) but there are numerous other areas where you can't just use a plugin.