Just had a fridge logic moment and now I feel stupid for not connecting this information sooner.
I've mostly been thinking of Salem's attack on Vale in terms of how it discredits Ironwood, but holy shit does it also elevate Ruby.
See when the animatic was first released some fans where doomposting about things being hopeless and everyone in Vale being dead.
Even then that was bullshit because the animatic clearly shows huge hordes of refugees in the distance. Those where the ones the Blind Worms where attacking and the ones Winter flew to protect.
The Boba episode makes it even more clear. If a shop owner can move their entire business to Vacuo and successfully set up shop in a short time period then clearly the evacuation was pretty successful. Tai's absence being framed more like a mystery in terms of "why didn't he leave" instead of "maybe he's one of the many people who died" also suggests that while Vale lacked the ability to stop Salem it did possess the ability to flee from her.
But how? Salem used overwhelming force that none could stand against, and she struck without warning didn't she? So how was the evacuation so clean?
See that's the thing. It wasn't without warning. Ruby sent a message. She warned the world about Salem, she let them know that Atlas was under siege and might fall. She took away Salem's element of surprise.
Ruby might have failed in her primary goal of getting help for Atlas. But she did succeed in her secondary goal of warning the rest of the world. It might not have translated into immediate success but it sure as heck saved a lot of lives.
Tl:dr: Ruby's message didn't just serve as a call for unity that encouraged people to band together. It also served as a very literal warning that prevented Vale from getting caught with it's pants down and being massacred by Salem's invasion.
So basically Team RWBY saved the people of Vale twice over. First by making Atlas actually fight so that Salem couldn't just use Monstra and her leviathan class Tempests to steamroll every other Kingdom. And secondly by giving a heads up.
No wonder people are making murals of Ruby and consider her message so important. Zam was right, she does deserve a cult.