I do expect a lot more movies after 2022(when we finally start to see movies produced and shot in a post-pandemic period) to feature a lot more themes of loneliness isolation and paranoia.Also a far grimmer and darker media landscape.
I don't think that will be about capturing the zeitgeist in major productions, so much as out of economic reality. The box office was already in decline and this is more likely than not to be its death knell; the movies that were in production or were able to complete principal shooting are going to be timed releases for next year's summer box office, and that'll probably be it assuming there is a summer blockbuster season next year and major studios don't just release the major productions early out of necessity. The writing has been on the wall streaming and digital download are the future for a while, with the only real holdouts being blockbusters and award bait; without those, Hollywood is overdue economic shock that will impact filmmaking technique and script choice.
The bottom line is, the genres and styles you cite are cheaper to produce, as they require fewer sets, tighter shooting requirements, less effects work, and smaller casts and crew. The economic, social, and political fallout from the pandemic is going to be far greater and longer-reaching than the outbreak itself, and it's not going to prove an unfair comparison to the Great Depression in the long term. So, how did the Depression affect Hollywood trends?
Escapism was the word of the decade. Historical films, musicals, animated features, and screwball comedies dominated the box office. Gangster and crime films were a vestige of Prohibition, and the Hays code took its toll on both leading to the growth of noir. Ealy talkies gave way to stereo by the end of the decade, but in contrast coloration in film all but stopped for a decade. Hollywood epics died out, to be revived at the end of the decade with Wizard of Oz and Gone with the Wind.
The through-line not being common themes, so much as low production cost.