Every year there's articles about how it's quiet & how asking prices are high & teams are wanting 1st rounders & bla bla bla & then the deadline goes just like every other deadline with about the same amount of trades & the same sort of assets changing hands.
Prices come down as sellers get desperate to move their players before they don't get anything. The day before the deadline if you're still asking too high, your buyers might all find their option B & you're stuck & nobody wants your player anymore.
another reason these NHL ready prospects have value is because of the contract limit of 50. Teams may not be able to acquire certain players because they are at the limit, so it frees up a contract as well.