Really? Last year started with a hot streak that barely let up--thus 108 wins. This year started with a terrible road trip, after which the Sox struggled to get above .500.
My guess, only that, is that fans are going to games this year partly because of the 108 and the WS last year. Plus the hitting is good. Plus some people like to watch train wrecks.
The Sox have now played 58 games at home with 23 to go, so there is still time for attendance to drop below last year's. However--
2012, losing season, attendance 37,567 per game
2013, WS win, attendance 34,979 per game.
2014, a losing season, it was 36,494.
2015, another losing season, 35,564.
2016, an ALDS season, 36,486.
2017, also ALDS, 36,020.
2018, greatest Sox season ever, 35,747
2019, disappointing season, so far 36,074.