The arXiv preprint by Bordoloi (2026) identifies a narrowing observational window for rest-frame EUV (1-4 Ryd) spectroscopy of z=1-2 quasars using HST/COS, where these sources shift into the far-UV bandpass. This work is a preprint and lacks peer review or quantitative sample statistics, yet it correctly flags COS sensitivity decline as a perishable constraint. Related work in the Milliquas catalog (Flesch 2023) and UVQS survey (Monroe et al. 2016) shows hundreds of UV-bright AGN at these redshifts remain unobserved at the required signal-to-noise, while COS throughput has dropped ~10-15% since 2010 per instrument reports. Mainstream coverage ignores this because it lacks the flashy signals of exoplanet transits or LIGO events, yet the datasets would anchor HWO's high-z EUV interpretations for decades. The gap is methodological: without expanded orbit allocations in the 2030s, no empirical SED census exists to calibrate warm-hot CGM/IGM absorption models. Limitations include unknown exact COS lifetime and reliance on future facilities like Rubin/Euclid for new targets. Synthesizing these sources reveals a strategic legacy choice overlooked in favor of shorter-cycle missions.