Clearly not.
Last year the Red Sox finished a distant, distant last in fWAR from the catcher position:
https://www.fangraphs.com/leaders.aspx?pos=c&stats=bat&lg=all&qual=0&type=8&season=2018&month=0&season1=2018&ind=0&team=0,ts&rost=0&age=0&filter=&players=0
... 22nd in fWAR at second base:
https://www.fangraphs.com/leaders.aspx?pos=2b&stats=bat&lg=all&qual=0&type=8&season=2018&month=0&season1=2018&ind=0&team=0,ts&rost=0&age=0&filter=&players=0
... and 27th in fWAR from third base:
https://www.fangraphs.com/leaders.aspx?pos=3b&stats=bat&lg=all&qual=0&type=8&season=2018&month=0&season1=2018&ind=0&team=0,ts&rost=0&age=0&filter=&players=0
Nevertheless the Red Sox were clearly superior enough at other positions to coast to a World Series title.