this is only true since the start of the mcu, prior to that dc movies were significantly more popular then anything marvel ever produced (not counting sony's spiderman).

the x-men have always been popular, the mcu has been an experiment in making new characters popular,

well things might be headed in the direction of dc again, chris hemworth is taking a break from acting, so there might not be a thor 5, and all the backlash they've been getting

i'm a little worried they're going to lose audiences if they keep the cinmatic universe going, feeling like they might be met with concerned investors that want them to give it a faster conclusion, so they can go back to evaluating movies on a case by case basis