OP's point is why are skins getting more attention than lore, at least at its core from what I can see. And the point I'm making is that such things are worked on by different teams, to different schedules and with different goals. Why are skins getting embellished so heavily when the lore's suffering? These things aren't intrinsically linked such that the skins are taking from the lore's lifeblood.
It's like when people complain about getting skins when the game is unbalanced or servers are breaking down. The people who fix servers or do live balance don't also make skins, and neither do the people who write the lore. The teams are of course working such that they're aware of what each other is doing, so they'll adjust the schedule so that stuff gets its appropriate time in the spotlight, but it's not like the Riot executives go to the lore team and are like "Alright no lore stuff because we're making magical girls". Riot's divided in to teams and wings and shit who do various things and work on their own terms, and collaborate when they want to.
I'll tl;dr this statement: OP's question is flawed in itself by asking a question to which the answer is "that's not how it works".