I strongly disagree. Spotify has dramatically increased the variety of music that I listen to and introduced me to lost of tiny artists with great music.
I'm looking at the official chart top 40 online and have to go down to 7th place to find an artist I know (Taylor Swift). Only one song on my "Release Radar" is in the Top 40 list (Sixteen by Ellie Goulding).
I think you get what you look for with Spotify. If you listen to a bunch of Lady Gaga and Taylor Swift, you'll be recommended a things like Aria Grande and AVICII. But if you listen to An Horse and Houndsmouth then you'll aparently get recommendations for The Mountain Goats and Me Not You.