Nobel-prize winning physicist Max Planck argued in his autobiography that change takes time because good ideas need enough staying power to outlive their detractors:
A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it…An important scientific innovation rarely makes its way by gradually winning over and converting its opponents: it rarely happens that Saul becomes Paul. What does happen is that its opponents gradually die out, and that the growing generation is familiarized with the ideas from the beginning: another instance of the fact that the future lies with the youth.
Clearly not always true, but it’s so broadly applicable a principle that it’s worth adding to your library of mental models.