maxdev, the solution is simple.
As long if there is one guy offering comparable quality asking for 15bucks for 10 landscapes, then 75 for 5 landscapes is expensive. If one asset like the linked Unity asset shows up for 15 on the UE4 marketplace, all other assets are goners.
And that’s just from a market point of view. From a personal point of view, knowing how easy stuff like is, I would rather eat 75 dollar coins and have them surgically removed afterwards (just joking).