Those Red Sox teams from the 1980s were different because even though they lost stars, they still paid to keep some of their best homegrown players -- Jim Rice and Dwight Evans -- not to mention icon Carl Yastrzemski, who played his entire career in Boston through '83.
They bottomed out winning 78 games in 1983 (not last place, though 6th out 7)... then were back in the World Series in three years, and won three division in five seasons.
Pitching, developed from drafting and the minors, was key. But the Sox still swung some solid trades -- not with prospects, but big leaguers (Eck for Buckner, Ojeda for Schiraldi, Lansford for Armas, Mike Brown and parts for Hendu and Spike Owen).