I think it's because we know that these 'fanbases' are trying to buy themselves the right to control their fave's life. They will be the same one sending trucks at Hybe's headquarters, complaining how their fave is mistreated, and would be sooo popular as solo artist instead because clearly BTS is dragging them down ect...
'We are spending an insane amount of money because we want to show he is more popular than the other members and create a power dynamic in the group' is what they're going for.
They are not trying to brag in front of other fandoms. They are trying to brag in front of other members and ARMY ( and other akgaes I guess )
you know i find it weird that you'd rather have these thoughts in your mind instead of just accepting that they're doing this because they simply love him, and cmon it's been more than 8 years you guys can't gate keeping the boys from solos forever especially when everyone of them has put out some solo materials, and no matter how much you hate it but in every group some members are gonna be more popular that others, it's just how life is, and please this is bts where talking about everyone of them is more powerful that 99% of other kpop idols, and i personally don't know why y'all sacred from solos like this since none of them is thinking of a solo career rn, and none of them is doing any sort of solo projects, it just doesn't make sense