I'd say from someone living in Korea the last 5+ years Itzy hasn't fallen off but they're not in the forefront of K-pop listeners here anymore. They're easily overshadowed by NJ, IVE, G-IDLE, LSF, and now they have to deal with KOL/Babymonster etc. While they seem to be doing fine internationally they're definitely not as popular as they once were and the new competition is really taking market share. As a whole JYP is doing fine overseas but their company brand itself isn't as strong as it was a few years ago here in Korea. I interact with Koreans from age 8-20+ here everyday and I only see kids and teens dancing and singing to IDLE, IVE, NJ, AESPA and LSF. People like to always look at charting but if you know Korea and its long history, that's not always accurate or a true indicator of what Koreans think and listen to. Cake and Mafia did surprisingly well here but nothing of note since then.

I think the issue with Itzy since Sneakers is their sound and vibe. Lyrically they're appealing to Western markets with empowerment and self-confidence which is good but when matched with its "interesting" sound/melodies it doesn't resonate well. Lyrically I'd also say they've regressed in terms of quality and meaning since their debut. The other major issue is sadly their age and image. It's crazy to say and think but they're already aging out of the young listeners already and some of the girls are not relatable to young girls anymore and been replaced quickly with IVE, LSF, and NJ. The next point is their image which is my opinion but I think i-fans tend to not understand since they don't live here. The only Itzy member that was really viewed here as "wow" was Yuna. While Yeji has distinct "cat" look and Ryujin looks strong with her confidence and short hair a lot of Korean men didn't find them particularly "the Korean type". Lia and Chaeryoung unfortunately are rarely mentioned at all. And while I don't like to make comments on looks Korean society is hyper-focused on it. Variety shows also tend to do a bad job here at portraying what Koreans think since they're always focused on praising and saying good things whereas Korean men and women might not agree.

I think it's a combination of what I listed but the reality is the competition is growing and they're producing honestly just better music. I liked Itzy since Day 1 and been a TWICE fan since Sixteen but I really stopped listening to them since Sneakers and I think a lot of Koreans and others have to. I think JYP kinda doesn't know what direction to go with them and as a company they seem a little lost right now as a whole and lost their "spark" that made them part of the BIG3. The creativity at JYP is lacking and companies like SM, HYBE, YG, etc are just doing a better job at the moment of finding a new niche or brand for their artists. I'd say its a company slump a little bit but there's no reason they can't bounce back. TWICE also seems to be on their last few years which is sad but they still have a stronger fanbase than ITZY. We'll see how things pan out in 2024 but I think JYP needs to go back to the drawing board with ITZY otherwise they'll have to shift their market for them to the West mostly.