I agree the Sox attendance is down this year because of poor play last year. Same goes for 2018, the Sox best season ever, but the attendance for 2019--36,106--was actually higher than for 2018--35,747.
I went to back to 2004 when the 86 year curse ended and found that the peak years started in 2008--37,632--after the second WS win. It stayed above 37,500 for five straight years--helped, the story goes, by a little padding (free tickets) by Sox management. It dropped in 2013 and stayed below 37,000 in 2014, the year after that unreal 3d WS win. And it hasn't returned to 37,000, let alone 37,700 in any season since 2013.
Covid hit in 2020, but at the same time John Henry made the decision to stop paying top dollar, especially for starters. The MLB standard for attendance belongs to the Dodgers, and in 2022 they averaged their normal, pre-covid attendance of 47,671. The Sox, who in 2021 made it to the ALCS (where they lost to Houston), averaged 32,408.
I think 32,000 is the new normal attendance for the Sox and it could drop further than that from a combination of not very good teams on the field and an absence of marquee players. I am absolutely not an expert on this topic, however.