CBS didn't update their cameras to support HD until ~2005. (Roughly the same time as the Sony lot). Exact timing varied studio to studio, and even when cameras were upgraded, the entire rest of the chain still had to be upgraded too and different shows had different needs (ie: not showing 84 year old Barker in 1080i).
One thing that definitely gets underestimated in footage from the late 90s and early 2000s is the difference between 480i (the broadcast standard at the time) and 480p. Go and spend literally any time on Youtube comparing the two and, genuinely, it might be the most underrated leap forward in video quality (because it was so rapidly subsumed by the 720/1080 and widescreen changes) in media history (at least since the change to color). And while the original transmissions would have been 480i, and while most GSN reruns back in the day at some point would have gone to 480i at some point before your eyeballs (where the choke point was changed over time), now you're seeing 480p tapes upscaled to Pluto's baseline 720p. So when you see Squares/Wheel/J! on Pluto, or other shows from that era, it's really the first time you're seeing the quality the episode was recorded and saved at - and why there seems to be an appreciable leap in video quality in reruns of many shows from the mid-late 90s onwards even when the broadcast standards hadn't changed.
(the difference that progressive scan makes over interlaced is one of the reasons 720p has held on for as long as it has vs. 1080i; but now that a lot of 1080i signals are flipping to at least 1080p, they're starting to be left behind or being put into a forced upgrade - to say nothing of 4K)
