As I said, I believe you can finish in 10 - 20 mins, I just dont believe most of players can.
Market gouging, plain and simple. The players don't need them now, but with pet skill training likely still in high demand, they'll sell for ridiculous amounts. Once pets stop needing scrolls + people run out of stable slots, prices should fall back to normal. For the people who've run out of 120's, you'll have to do spawns to get more (or pay an arm and a leg), and you could theoretically go 10+ spawns without seeing anything higher than a 115.
Honestly, it really isn't THAT hard to speedrun spawns, although it depends on which one you're doing - Oaks will take a bit of time because of terrain + your willingness/unwillingness to lose karma. Your time also varies based on the templates you bring. An archer? Great for the bosses, not so much for the spawn itself. Same with a thrower. Leveling the spawn can be rough on a melee whammy (which is also great for bosses), but you still have bandage heals, curse weapon, and whirlwind (I still prefer a sampire for mass mob killing though.)
The plain and simple fact is that if most of players can easily get the scrolls in 10 - 30 mins, the price would not go so high.