I haven't followed this season as closely as the last few seasons, but Ajax have now won a total of 7 games in a row in the league, so they're already picking up a lot of points. Contrast that with PSV with three draws and one loss in their last 5 games. If Ajax's form continues, it will be difficult for PSV. Everyone else is already too far away for the title, in my opinion.
Obviously Ajaxs has actually improved a whole lot and has accumulated a good number of points such that theybbare now having a very good chances of possibly finishing tops of the league even if they don't eventually in the league title but then they will get in-between the top four. If PSV continues to draw and reduce their point they have chances that Ajax will likely take over from them.