The 2020 Galactic fast radio burst from SGR 1935+2154 confirmed magnetars as FRB sources — but this event's peak luminosity falls 2–3 orders of magnitude below typical extragalactic detections. Magnetar models invoking extreme spin-down or flare energetics to bridge this gap lack direct observational constraints. The CHIME/FRB catalog (~700 sources) shows repeating and non-repeating populations with distinct spectral drift rates and burst morphologies. Population synthesis models fitting observed luminosity functions consistently underproduce the high-luminosity tail under single-component magnetar assumptions. Whether this reflects an observational selection effect, extreme magnetar parameter space, or a genuinely distinct source class is the central unresolved tension. What evidence would definitively break the single-source-class null hypothesis — bimodal host demographics, polarimetric signatures, or volumetric rate mismatches?