In conventional BCS superconductors, superconductivity is stabilized by lowering interaction energy, whereas the electronic kinetic energy increases in the superconducting state. In cuprates, by contrast, whether superconductivity can be accompanied, or even driven, by kinetic-energy saving has remained a central open question. Pioneering optical-conductivity sum-rule studies first opened this perspective by indicating that kinetic-energy changes may be intimately connected to the superconducting transition. Building on this foundation, we use exact sum rules of the electron spectral function to extract momentum-resolved changes in electronic kinetic and interaction energies directly from spectroscopy, in a model-independent way. We show that, in both optimally doped and overdoped cuprates, the superconducting energy balance is dominated by interaction effects near the antinode, while the kinetic-energy contribution reverses sign with doping: it is reduced at optimal doping but enhanced in the overdoped regime. Comparison with mean-field BCS theory and the attractive Hubbard model further shows that electron-electron interactions alone are insufficient to reproduce the observed sum-rule behavior, highlighting an essential role for electron-boson coupling.