Total monthly posts exploded after Spez enshitified Reddit, and is still growing steadily month over month.
That suggests that the current decline in monthly active users is primarily because lurkers who only came to lemmy after initially hearing about it on Reddit, went back to lurking Reddit.
The number of users that are contributors is still growing, and that’s what’s important.
It’s not quite as crazy as it seems. The older/larger floppy disk formats were more reliable due to their lower track density.
There was more surface area per byte of data. The old floppy disks could be written once and read for years in harsher environments. New floppy disks we more prone to failure after a few years.