Marvin Gaye: "What's Going On?" / "What's Happening Brother?"

I was researching the electric bass, in particular James Jamerson, who played in the rhythm section on most of the Motown hits. Here he is in a gorgeous and timely Marvin Gaye performance (from 1969 or 1970)...

[Not to break the reverie, but who IS Google paying to run clips like this? Marvin Gaye's estate?]

Here is another performance of "What's Going On?" from 1974 (several years, I would guess, later). Do you notice what I do? Jamerson is not playing here (and the song is totally un-hinged, all over the place) and Marvin Gaye looks worn out.