In standard ΛCDM the cosmological redshift drift should be nonzero for most redshifts, changing sign between the decelerating high-z past and the accelerating low-z present, so a persistent null result at all redshifts would strongly disfavor the FRW+? framework and instead support alternative “coasting” or non-FRW cosmologies that predict essentially zero drift (Loeb 1998; Liske et al. 2008). Recent ESPRESSO pathfinder measurements already find a drift consistent with zero within current errors, highlighting how difficult it is to distinguish a small but nonzero ΛCDM signal from an exact or effective null prediction over realistic baselines and raising the possibility that even future experiments could find values compatible with zero within uncertainties, complicating efforts to use the Sandage–Loeb test as a clean discriminator between models (Uzan et al. 2008; Martins et al. 2024).