It's closer than ever, in my opinion. Southampton illustrate this perfectly.
Last season, Southampton finished 8th place - historically, a respectable finish - but were still only 6 points off relegation. A couple of last minute goals over the course of the season could've seen them get relegated, but in terms of league position they were just outside the European qualification places.
This season, they've amassed a whopping 4 wins from 17 games, with -6 goal difference... which historically screams relegation form - yet they find themselves in 11th place. It's mad.
The Premier League has basically become two leagues in one, with Man City, Man United, Chelsea, Spurs, Liverpool and Arsenal all at the top, and then "the rest" following behind. But in terms of who can relegated at any given time, it's closer and more interesting than ever.