Observations show that many massive disk galaxies either lack classical bulges altogether or host bulges whose kinematics, ages, and shapes are largely decoupled from their surrounding disks, with pure disks and pseudo-bulges being common even at late times (Kormendy & Kennicutt 2004; Kormendy et al. 2010). In hierarchical ΛCDM, frequent mergers and low–angular-momentum tails of dark matter halos are expected to build substantial classical bulges tightly linked to the disk’s assembly, so the high fraction of bulgeless or weak-bulge systems and the apparent independence between bulge and disk growth histories pose a challenge to standard galaxy-formation scenarios (Mayer et al. 2008; Brooks & Christensen 2016).