It’s surprising to me, too. For years, drama was an afterthought in the spec market. No longer. My guess, I think there is some blowback against all the spectacle movies (i.e., superhero, action, franchise films). Moreover the most loyal audience to actually go out to movie theaters are people who have grown up with movies as a central part of their entertainment lives, so adults from 40+ years old. And those type of adults — big generality, I know — tend to like adult dramas.
Also there is a sweet spot for historical dramas which can be made for a budget $25M and less, especially if they have a clear primary audience, like Hidden Figures (women, people of color).
I argued some time back that some studios may start to go back to a strategy of producing more ‘singles’ and ‘doubles’ type movies (link). Maybe we’re seeing that now.