Imagine a Judo competitor who dominates the national scene and wins 15 titles in a row. However, when he goes for the European title he gets beaten and embarrassed repeatedly. Would people use the same argument? This thing about la liga being more important is nothing but a Catalan coping mechanism.
Bayern and Juventus absolutely dominated their leagues but noone but their fans care. The neutral will point out how Juventus were soundly beaten by both Barca and Madrid in CL finals.
With amigos we dominated la liga cause teams were easier to beat. As soon as amigos had to match the workrate and intensity of top European teams they collapsed . This whole league is greater than CL is absurd.
Sadly for us, Barcelona want to win LaLiga as it is anti establishment and the mentality is not just beating Madrid but the state who put the odds in their favour.
It's an institutional thing that we as fans can see how they have added influence. But the Catalans feel it, with their prior oppression and current self-oppression.
The years we were out of LaLiga contention we did prioritize the CL and did well in it. Think LVG reaching the Semi when Valencia surprised us, or Rijkaard taking an average Barca to the semi against Man UTD.