This is true but ironically "Ether" did chart off Airplay and hit #50 on the R&B and Hip Hop Charts. "Hit Em Up" was also the B-Side on the #1 Hot 100 Charting Maxi Single for "How Do You Want It". Canibus's "Second Round K.O." hit #28. Speaking of LL, Kool Moe Dee's LL Cool J Disses "How Ya Like Me Now" and "Let's Go" both made the R&B Charts in the 80's. So yes to your overall point, Diss Records are always hard to chart on the Hot 100 because that's mostly a Pop Chart and they either don't release it as a single or it's too vulgar for airplay. Also as people mentioned. "Hiss" did go #1 this year and that was technically a Diss record. But this year made Hip Hop History. There have been 6 Diss Records in the Top 10 just this year:
#1 Hiss
#1 Like That
#1 They Not Like Us
#3 Euphoria
#6 7 Minute Drill
#7 Family Matters
"Meet the Grahams" is scheduled to Debut at #12 just missing the Top 10. "Push Ups" has peaked at #17 thus far. What makes this so huge is K Dot did it on a short week basically by dropping the song late Saturday so the tracking didn't start until Sunday. The only problem is he stepped on "Euphoria" so it probably won't get a #1 but #3 is still good.