@Seif
Agreed, there’s always help. 😉

@Yet One More Idiot
They probably were meant to be one time appearances.

@Dead Profile
Nah they did horrible things

@CORDZ2000
Mi point is that they never did anything so bad that they would be “banished” “defeated” or whatever. It’s just the usual petty teenage stuff.

@Dead Profile
And yur point?

@CORDZ2000
But they are just teenage girls

@Yet One More Idiot  
or be reformed but not tamed like discord i know he became controversial for it over seasons but it was a popular idea for him at first, its a way to have a character keep traits that what made them great villains while ultimately at the end of the day being on the side of good. Or more clearly intended chaotic neutral like how the dazzlings are now.
 
But yeah to answer the question its because writers don’t really know what to do with them so in order to make them no longer a threat they just reform them and be done with them its incredibly lazy yes

@CORDZ2000  
Yes, this is what I’m saying.
 
Villain reforms at the end of their story and is involved in subsequent stories as a good character? Sure. (Sunset Shimmer, Starlight Glimmer, Trixie)  
Villain doesn’t reform at the end of the story, and returns as a villain in later stories? Sure. (Chrysalis, Cozy Glow, Tirek)  
Villain doesn’t reform at the end of the story, but is never seen in the show again? Sure. (Sombra)
 
Villain reforms at the end of their story and is never seen again….why? What was gained by having them reform and then vanish completely off the radar? It’s a waste of a character reformation.

@Yet One More Idiot  
I think its better to keep a character as a villain and have them defeated if they aren’t gonna appear again. I think its weird how some writers try to write off characters by reforming them because them it begs a question of how they are as reformed characters. At least with them being defeated and locked away or something there is a excuse of why they haven’t come back.

Imagine they all appear in the IDW comics

@Yet One More Idiot  
If they became friends, they can help The Humane 7 in their problems as returning the favor for teaching them the importance of friendship.

All redeemed! Mostly…forgotten. xD
 
Creating villains with the purpose of having them be redeemed at the end of the story is a good idea for creating marketable characters, but only if you actually use the redeemed villain frequently thereafter.
 
Case in point: Shim-shim. Or Glimmy. These girls got redeemed and became major characters in EqG and FiM respectively afterwards. Even Trixie eventually redeemed and became besties with Glimmy and additional support to the Mane 6.
 
Most of these girls appeared once, got redeemed, and then pretty much vanished into the background again; even the ever-adorable Blushie. Re-use some of your support characters, Hasbro! Sometimes, less is more!