I think I agree. Just saying what my understanding of the assertion was. Basically, that there are only so many "meaningful" positions on the board. And at the upper levels, the question becomes more of how many of those positions have you memorized. Not, "how does your opponent play?"
As opposed to a game such as tennis. Where you really have to consider not just what you are capable of against a volley, but what your opponent will do with it.
No, chess is not about memorizing position and most games leave memorized territory fast. I don't know why this idea that chess is about memorizing openings got so much traction, it's nonsense. Top level games are rarely decided in the openings these days (although it happens that someone got nailed but usually it's because choosing very sharp variation and then forgetting the analysis) and there is a lot of play in positions never seen before in most of them.
Top level games are rarely decided in the openings because top level players typically don't make bad ones. :)
Is this akin to saying that top level tennis games are rarely decided by double faults. Likely true, but completely ignores the point that learning to serve over the net correctly is a vital skill. Just as learning a vast repertoire of studied moves and board continuations is key to chess.
As opposed to a game such as tennis. Where you really have to consider not just what you are capable of against a volley, but what your opponent will do with it.