Makes sense to me. Unless you're a big brand who can offer more than just change (e.g. prestige, reputation, etc), the good ones are all too busy working and/or freelancing for themselves, they won't bat an eye for $100.
Side Project
A community for sharing and receiving constructive feedback on side projects.
Would you produce a high quality video about some product you don't care about not for $100 but for a mere possibility of winning $100? If not, don't be surprised that not many people find your offer interesting either.
As an employer at Freelancer.com with over 900 projects done, I can assure you that typically in this type of platform you get what you pay for: A high price doesn't guarantee high quality, but low price will almost always guarantee low quality.
How specific are you being with the video?
Ideally, you provide creators with a brief with guidelines on things like what phrases to use and anything that could help them (images, hooks), without being specific enough to limit their creativity/creator potential.
Seems like you have an expectations problem, and if you still have 29 days to go and are getting 5 submissions a day, you can just wait and see if it gets better. 80/20.
You may do better just paying a professional $100. On a site like Upwork or Fiverr. Ask them to produce the asset. Posting it and promoting it is your job, not the artist's job.