Whose decided Cassini's flight path?

I just found out that Cassini will *never* fly close enough to get a
picture of the rings that resolves individual particles (large rocks or
ice chunks). Why not?? We spend millions to send a probe some
kazillion miles away and we don't even visit the best sites. It is
like going to the Grand Canyon on vacation but never leaving the hotel
room. Unbelievable!!

BigKhat