I've often noted the same thing. The 1968 Willie Mays using the same picture as his 1965 card, and the 1969 Mays re-using the picture from his 1966 card, are two of the most egregious examples. The identical 1968 and 1969 Hank Aarons also come to mind.
Here's a really interesting article that partially explains the phenomenon in the late 1960s:
https://sabrbaseballcards.blog/2017/...cott-of-topps/