Does hopepunk contribute something different than being a memeified response to grimdark?
What on earth are you talking about?
You're "memeifying" hopepunk, it's not "memeified" itself. You can't accuse other people of doing what you're doing. Good lord. Also how can you complain about "memes" when you seem to singing the praises of grimdark, the most "memeified" genre in human history!
Joking aside, stories where the world is effed and bad people are in charge but our plucky protagonist can rise up and overcome them are as old as the tides, no?
Absolutely. But because there was a brief era of super-rape-obsessed grimdark being dominant in the early 2000s (long, long after Dark Sun, which is not grimdark, and only weird revisionists claim is). It's a bit weird that people are calling that structure hopepunk but they are because of the once-dominance of rubbish like Malazan.
Grimdark is a new(ish) type of story
No.
Absolutely not. Grimdark as a term is refers to Warhammer 40K's "In the grim darkness of the 41st century..." which is from the mid-1990s, and frankly, tonally, there have been stories like that for decades and decades, because 40K didn't invent the genre, it just named the trope.
What was "new-ish", and let's not prance around this, was
being obsessed with rape (and also more general torture), primarily of women, particularly young women. That's what marked the big difference with early 2000s grimdark, which is the only thing I can imagine being called "new-ish". Steven Erikson, R. Scott Bakker, Mark Lawrence and so on were absolute rape-obsessives (Lawrence later recovered and became a bit more normal, the other two did not). Richard K. Morgan, who was slowly losing the plot, got in a bit later and wrote the same way (very distinct from his SF I note). I blame GRRM for starting this, but he was never as bad as these lot.
Luckily, Joe Abercrombie wasn't obsessed with this, was a better writer and storyteller than any of those freaks, and seems to have altered the course of modern darker fantasy fiction (grimdark or just dark) by being extremely successful and popular.
Horrified to hear anyone is still reading Prince of Nothing in 2025. It's stylish ultra-trash that has absolutely nothing to say despite massive, gigantic, crushing pretentiousness which could easily make people think it might. I sadly made it all the way to book 4 before I realized we were going to get nothing but more Tolkien pastiche, stolen-from-700 AD history stuff (rise of Islam, decline of Byzantium), cod-philosophy, admittedly cool wizard-fights, and sexual assaults of various kinds. That no-one shot Anasurimbor Kellhus with one of the man-portable laser cannons that the first book says exists fairly early on remains a great disappointment to me (apparently it doesn't happen in the other two books either).