People keep inventing new ones because the old ones suck or they think the old ones suck. Look at all the discontents around JSON (no comments!), people react violently when people try to apply a little extra like JSON-LD. Then there are all the things like YAML, TOML and such that try to be a little better but are widely thought to be a little worse. (And that's just the human readable data formats) Then there is always

https://en.wikipedia.org/wiki/ASN.1

which is forgotten but not gone.