No, almost every piece of non-live media that was produced from the 1940s onwards went into huge broadcast archives. Some of the media it was stored on was destroyed, or otherwise reused for newer broadcasts, but much of what survived wasn't due to the inherent quality of the content and we have vast amounts of it remaining. Take this compilation of 1960s commercials from the Prelinger archives [0]. These obviously weren't produced to the same quality as the Chevrolet videos, but it's also not drastically different from contemporaneous syndicated content. The pacing is slower than modern ads, most include practical demonstrations of why the product is better/necessary, and there's just less optimization towards the visual frenzy we see today.
[0] https://youtu.be/EGUuyewrNNo