They became split after 2019, with a roller-coaster track of (some) highs and (more) lows, specially if we are counting the marvel disney tv series too (since they are inter-connected now, we should). No genre or franchise ever died suddenly, even DC had successes years after BvS ‘Martha is our mother’s name’ event (which also did make money itself, the loss of goodwill only shows up in later entries).

My analysis is that most of the successes are prologues of pre-2019 stories and characters, redoubling the appeal to nostalgia and giving an ending where Marvel lets (guardians 3, deadpool for fox marvel, spider man with the 3 spiders and ending current peter’s arc). The actually new stories and characters, that should be the ones being widely seen cause they are supposed to star and steer the MCU now, have been duds. This is a strong indicator of decline, and the fact they threw money bags at Robert D. Junior to appeal again is another.