Sure, it's bean counters. So then go a step further, and ask yourself: why are the bean counters afraid to take risks on fresh creative content? What market forces are driving them to bet solely on licensed shlock in the post-2000 world? What changed?
If the publishing industry is overwhelmed with a flood of writers--it very much is--well, please ask "why." Dig into the reasons behind the indie author gold rush.
There's a great in-depth recent history of the publishing industry here: https://www.wattpad.com/869503247-so-you-want-a-fandom-publi...
Quick and dirty summary:
Amazon opened its floodgates in 2009, when it offered 70% royalties. Traditional publishing gives authors somewhere around 5% royalties, when all is said and done. That is how the gold rush started.
As for publishers betting on tried and true best-sellers... that started earlier, when several laws in the 1980s caused a major consolidation of businesses, including publishers and booksellers. A law got changed, and Barnes & Noble became the arbiter of what got shelf space.
There is a lot to this history.