Well, clearly the difficulty is happening to everyone except Ajax because they are currently having a blistering second half of the season campaigns. If I remember correctly, PSV was ahead with over 9 or double digits points but that gap is now super tiny.
If PSV doesn't sit up and Ajax continue this fine form, I won't be surprised if they later get to win the title.
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.
Ajax is in great form. PSV, on the other hand, has become very bad later on. They started the league very well but could not continue. Ajax is currently in the lead despite playing one less match. If they complete their missing match and win, the point difference between them and PSV will increase to five. Ajax seems to be the strongest candidate for the championship this year. As long as PSV continues to regress in the game they play, Ajax may even reach a higher point difference.