[old_tv_nut]

In terms of how much tape itself degraded the TK-41 output, I would say that a keen eye can differentiate which degradations come from where. The main TK-41 limitation was signal to noise ratio. Tape could contribute things like moire patterns in high chroma areas (on the low-band machines), or head banding when the four individual heads did not match, which could show up as hue shifts or differences in SNR, but would be identifiable by the different bands in the picture. Other tape issues could be edge effects like ringing or overshoots due to the sharp filters in the tape machines.

Most of the degradations you see on youtube come from multiple generations of other tape formats through which the material has come down to us, and/or digital artifacts due to insufficient bit rate.