You're absolutely correct. "Alternative" appears to be an amalgam of many different musical styles and genres. I used to listen to The End quite a bit for some of the newer rock music content, but would immediately tune out when an electronic song was aired. I'm pretty sure that BigA, David, and many other experts always cite consistency as being an essential component for success. I hardly think that you could classify The End as consistent, when the music is all over the map and they can't decide what they want to be. You're right, we know that 6+ isn't providing a complete picture, so perhaps the situation isn't so bleak.
I was a child in the late 90's/early 00's, when Outkast would bump into The Strokes, and Creed would lead into Fatboy Slim, so my taste is probably more eclectic than the average Alt listener, but the general mixes at Entercom Alternatives right now baffle even me. Firing the vast majority of local talent and replacing them with "regional" voice-tracks that even intermediate listeners will realize are not from the area, plus radical playlist changes without warning, didn't help either.
Here's a couple of sample hours I pulled from today's playlist, it becomes rapidly apparent what the mix's problems are IMO.
9-10 AM @ KNDD:
1. Foushee - "Deep End" (2020, C)
2. blink-182 - "What's My Age Again?" (1999)
3. Billie Eilish - "everything i wanted" (2020, R)
4. Imagine Dragons - "Demons" (2013)
5. KennyHoopla feat. Travis Barker - "Estella//" (2020, C)
6. Lorde - "Tennis Court" (2014)
7. absofacto - "Dissolve" (2019, R)
8. Switchfoot - "Meant To Live" (2003)
9. Juice WRLD & Marshmello - "Come & Go" (2020, R)
10. Foo Fighters - "My Hero" (1997)
11. portugal.the.man - "Feel It Still (2017)
12. Green Day - "Holiday" (2004)
13. Cage the Elephant - "Skin And Bones" (2020, C)
14. Lit - "My Own Worst Enemy" (1999)
15. Matt Maeson - "Cringe" (2019, R)
16. Bishop Briggs - "River" (2016)
10-11 AM:
1. Machine Gun Kelly & blackbear - "my ex's best friend" (2020, C)
2. Nirvana - "Come As You Are" (1991)
3. Cannons - "Fire For You" (2020, R)
4. Rise Against - "The Violence" (2017)
5. AJR - "Way Less Sad" (2021, C)
6. blink-182 - "I Miss You" (2003)
7. Two Feet - "I Feel Like I'm Drowning" (2018, R)
8. Florence & The Machine - "Dog Days Are Over" (2009)
9. Benny Blanco w/collaborators - "You" (2021, C)
10. Red Hot Chili Peppers - "Under The Bridge" (1991)
11. 24kGoldn & Iann Dior - "Mood" (2020, R)
12. KALEO - "Way Down We Go" (2016)
13. Billie Eilish - "Therefore I Am" (2020, C)
14. Death Cab For Cutie - "I Will Follow You Into The Dark" (2005)