It turns out that when the Olympics first appeared at the start of the century a number of events involved artists (painters, writers, architects, sculptors) competing for medals in refined battle royale. Sculptor fought sculptor, amphitheatre vs amphitheatre.
The marking scheme was haphazard and many prominent flock did not partake, so in 1952 the whole thing was scrapped, and perhaps to enliven an otherwise unelevated spectacle, the opening ceremony rose to is current fame.
This kind of fusion is interesting to consider, however - the young samurai composing a cherry haiku after his latest tussle. But the games have become too specialised, too honed in for each event on one single set of skills and movements, for any other competition to emerge, and even the decathlon has lost its former flame.
To the question 'what is art?' google returns an arcful of books and polemics, scribes and sighs, but 'what is sport?' returns only a shadow of that, and perhaps there the difference sits, forever.