Despite decades of study, the underlying pairing mechanism in the bismuthate family Ba1-xKxBiO3 (BKBO) of high-temperature superconductors remains unresolved. In this talk, I will discuss recent work reexamining the role of electron-phonon coupling in this system, both in the parent and doped compounds. I will begin by presenting new nonperturbative hybrid Monte Carlo calculations (HMC) for a multi-orbital model that includes the Bi 6s and O 2p orbitals with coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the hopping integrals [1]. Using a state-of-the-art HMC implementation [2], we treat large three-dimensional clusters of up to 4000 orbitals with realistic model parameters taken from ab initio electronic structure calculations. Our results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in the parent compound and highlight the critical role played by the bond-stretching oxygen modes. I will then discuss the results for the doped system in conjunction with new total neutron and resonant inelastic x-ray scattering measurements [3]. Here, we find evidence for a (bi)polaronic normal state, implicating the bismuthates as a novel class of bipolaronic superconductors.