I think that's the core question right there. For a while, various governmental bodies got to be the authority figure deciding which ideas were widely propagated. It's interesting to consider the outsized influence of Texas school boards here; the people who decided which textbooks would be used in Texas were elected officials. Texas has a huge textbook market. Accordingly, textbook vendors were incentivized to publish textbooks which fit Texas standards, and other states who didn't have the same influence wound up with those textbooks.

So: "who decides what is and isn't a silly idea?" Texas elected officials.

That's suboptimal in my view. It is also not great that four or five major companies have the same decision-making power. Fixing the problem is difficult, but I take some comfort in knowing that it's not actually a new problem.