It doesn't make sense having to get 13 additional boosts (+2 that comes from nitro) costing an additional 45.37$ per month on top of nitro just to get 1080p go-live in a small server that might only have a few streams a week between ~20 friends.
The cost of the server boost features to discord are obviously volume dependant (1000 people streaming HD video will cost more than 1 or 2). So it doesn't make sense when the boost are the same, regardless of server size.
The boost requirements for each tier could scale based on server size. (i.e. servers with less people could have an initially lower boost requirement which would then scale up to the current level when there are more people)
Which, economically, I assume would actually make more sense for discord. Making it more likely people will buy additional boosts for smaller servers.