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.
That's right, it could be that in the future Atletico Madrid will get the advantage to take over the top of the standings, when we focus too much on Barcelona and Real Madrid. But what is certain is that the top three teams seem to continue to compete until the end of the season. It is still difficult to guess who will finish in first place, injury problems, a tight match schedule, will always be the main challenge. Real Madrid benefits because they have one postponed match, on paper the match will help them overtake Barcelona. Of course, all of that is just an initial prediction, and everything can change very quickly, at a glance the three teams have the same big chance for now.
If I'm honest, I'd rather Atlético de Madrid win the league this year or at least be in a position to win it until the end. I just checked and in the last 20 years 18 leagues have been won by either Barcelona or Madrid, and only two have been won by Atletico Madrid. A bit of variety for the title contenders doesn't hurt. Before that and in the early 2000s still won the title Valencia, which is not at all nowadays, and Deportivo de la Coruña, nowadays in the second division, so it all seems that the league is a matter of two and a third very occasionally.