Yeah, they began 2 when only 1 episode had aired and were halfway through it by the time 1 ended.
Don't have to be in the audience to know they suck. I'd bet some of the people on the crew/maybe Nefcy herself hated forcing them into stories and so decided to do away with them as soon as they could.
If I had to guess, I'd say they were conceptualized quickly as Marco's friends by one of the people responsible for helping her develop the show for television. Nefcy probably wasn't particularly attached to them, the way she would've been with Star/Marco, they largely didn't add anything to the episodes they were in, their character concepts themselves didn't offer potential plotlines (regardless of how you feel about Jackie, "Marco's crush since kindergarten" at least provided enough material for a continuing storyline).
So when Nefcy was the only one in charge, she and the crew probably either decided to axe them or cared so little about them/didn't see the need to include them that it was several episodes before they even noticed and decided to keep it that way.
Season 2 as a whole did a great job of fixing problems with the show.