You can't really expect immigrants to fully integrate into the new culture overnight. Toronto is a massively multicultural city - you will find people in various stages of "assimilated Canadian" wandering the streets, from the newly arrived (hanging out in Chinatown, little Italy, Polish village, not speaking much English, not watching hockey, eating bacon, etc.) to the fully assimilated (speaking English, talking about the weather, comparing oneself to Americans, watching Rick Mercer, etc.).. to everything in between.
Does it mean that multiculturalism has failed just because places like chinatown exist - as well as people in various stages of being assimilated (or not being assimilated at all)? Nah, that's just reality. The truth is that people like to hang out with people who are like them - newly arrived Poles will naturally be more comfortable hanging out with other Poles and spending a great amount of time in the local Polish community. My parents have a LOT of friends who speak English with a broken accent, only watch Polish tv, only listen to Polish music and leonard cohen, eat very traditional Polish food, etc. It is awesome that these people exist because it creates a demand for very Polish things around here - Polish grocery stores, dance clubs, tv stations, etc. It adds a unique flavour to this city.
But these people's kids, who were born here? They speak English (sometimes Polish too), eat pizza, watch hockey, and feel pretty damn Canadian. The generation after that? Even more Canadian - whatever being Canadian even MEANS - which is another debate entirely. The point is that people will assimilate given enough generations.. sure, some cultures are faster at it than others, but that's just reality.
Chinatown, people not being fully integrated, etc. is not a sign of failure - it is a sign of progress.