With such a narrow points gap, it's bound to create a healthy rivalry between the two. Madrid are also trying to get up and Barcelona are trying not to let their guard down in their current position. It could be that Madrid cannot catch Barcelona because the remaining 1 match is still uncertain 3 points.
I partially differ from what you say. For starters, there is already a third party in play for the league, Atletico Madrid, who are only 2 points behind Barca, and as you say, we will have to see how the pending Madrid-Valencia match goes, because if Madrid win it, they would now be leaders, but I think there is still a month to go before it is played.
It seems to me that last year it was the same, wasn't it? Barcelona did well at the beginning and lost the league at the end. If it wasn't last year, it was the year before.