Rewards Impossible to Achieve

If I want the skyscraper that serves as the reward for completing the Season Collection in the City Album, I need the Riverwalk. To get the Riverwalk, I need 29,950 snowflakes. I currently have 5135. Even if I purchase the Premium Mayor's Pass+, the rewards I've earned will bring me to 19,435. I'm sure as hell not getting 10k snowflakes in five days by doing Chicago tasks, so where are the remaining snowflakes supposed to come from? Did anyone who tested this acquire the Riverwalk without putting 18+ hours a day into the game? Did anybody test this at all? All I see is a season reward that is going to be out of reach to me before the first week is over. Somebody make this make sense.