Complex sentence: From 1998--2003, they played neighboring Sandwich High School on Thanksgiving, but both teams dropped the rivalry after 2003 due to Sandwich being a much larger school than Mashpee, and also to the lack of competitiveness.
Split into simpler sentences: From 1998--2003, they played neighboring Sandwich High School on Thanksgiving. Both teams dropped the rivalry after 2003 due to Sandwich being a much larger school than Mashpee, and also to the lack of competitiveness.