It's not just about the format. Old internet
memes (circa 2006-2015) were generally less obnoxious, less obscene, less grotesque, less stupid, less deadpan, less political, and just generally more graceful and lighthearted. You never took them seriously, and they always made you smile or laugh (NOT smirk!)
Today's
memes often leave you smirking rather than smiling or giggling, as the
meme often plays with the more ironic, farce and brazen side of humour. This makes for a less "happy" experience as such. Certainly not something you'd be consuming/posting unironically, unlike nyan cat, animal advice, and lolcat
memes.
Another difference between modern and old
memes is the level of irony. Obviously
memes of all kinds is not meant to be taken seriously, but most modern
memes will add a layer of irony on top of a seemingly serious context to make it seem funny or silly. Old
memes are just funny or silly by its very nature.
Old
memes can be virtually understood by anyone of any demographic and the humour is often naturally communicated by the image. Modern
memes tend to be too ambiguous to be understood correctly by everyone and the humour is specific to a certain demographic (i.e. Gen Z teenagers). Serious debriefing is required to understand most modern memes, even the ones with zero meaning.
Overall, old memes just had that quirky yet graceful charm that modern memes lack. Old memes rule,
don't let anyone tell you otherwise (and if they do, they're probably a zoomer).