Sure, lossy compression is lossy, but that wasn't my point. My point was that data corruption in information-dense formats is more critical than in low-density formats.

To take your example of the vacation photos: If you have a 100 megapixel HDR photo and you lose 100 bytes of data, you will lose a few pixels and you won't even notice the change unless you zoom in quite far.

Compress these pictures down to fit on the floppy from your example (that would be ~73kb per photo), then losing 100 bytes of data will now be very noticeable in the picture, since you just lost ~0.1% of the whole data. Not taking the specifics of compression algorithms into account, you just lost 1 in every 1000 pixels, which is a lot.

High resolution low information density formats allow for quite a lot of damage before it becomes critical.

High information density formats on the other hand are quite vulnerable to critical data loss.

To show what I mean, take this image:

I saved it as BMP and then ran a script over it that replaces 1% of all bytes with a random byte. This is the result:

(I had to convert the result back to jpg to be able to upload it here.)

So even with a total of 99865 bytes replaced with random values, the image of an apple is clearly visible. There are a few small noise spots here and there, but the overall picture is still fine and if you print it as a photo, it's likely that these spots won't even be visible.

As a comparison, I now saved the original image as JPEG and also corrupted 1% of all bytes the same way. This here's the result. Gimp and many other file viewers can't open the file at all any more. Chrome can open it, and it looks like this:

The same happens with audio CDs. Audio CDs use uncompressed "direct" data, just like BMP. Data corruption only affects the data at the point of the corruption. That means, if one bit is unreadable, you probably won't be able to notice at all, and even if 1% of all data on the CD is corrupt, you will likely only notice a slightly elevated noise level, even though 1% data loss is an enormous amount.

If you instead use compressed formats (even FLAC) or if it's actual data and not media, a single illegible bit might destroy the whole file, because each bit of data depends on the information earlier in the file, so if one bit is corrupted, everything after that bit might become unreadable.

That's why your audio CD is still legible far beyond its expiry date, but a CD-R containing your backup data might not.

Again, these data retention time spans don't mean that after that time all data on the device disappears at once, but that until that time every single bit of data on your device is preserved. After that you might start to experience data loss, usually in the form of single bits or bytes failing.

Edit: Just for fun, this is what the BMP looks like with 95% corruption:

Even with this massive amount of damage, the image is still recognizable.

Edit 2: Due to a mistake in the script, this image is actually 61.3% corrupted, not 95%, but that's still a massive amount of corruption and the image is still clearly recognizable.