In pairs, being able to do the jumps/lifts/throws is only half the battle. The other half is developing what I think of as the "pairs quality" of the team--basically, joining the skills of the two skaters to create perfect unison, connection, timing, and line *as a team*. The greatest pairs aren't defined by their technical elements, but rather by the overall quality of their pairs skating.
Despite their many years together, Zagorska/Siudek never really developed great pairs quality in their basic skating. For example, they were often out of unison in side-by-side footwork, and often looked tentative and slightly out of sync going into pairs spins. Even their side-by-side spirals suffered, as Siudek's leg line was never aligned with Zagorska's.
To me, it was this lack of great pairs quality in their skating that kept them from becoming champions.