Exactly this. When I take a look at my niches all I can see is spam and spun content in the Top 10. People share trash on Pinterest and Facebook, do keyword stuffing and its ranking in the Top 10. Legit and relevant websites are somewhere on page 4-6.When Google says: "we have an update" they are just shuffling listings around to force businesses to buy their ads.
There is no update, it is just a shuffle of the deck.