Fair comment....agree with the credit unions and such. I don't know if another bank like the 5 could open in Canada; I mean, there might be legislation or something restricting it, so that is why the credit unions and such have opened. The only difference is, they are owned by their members.They are publicly traded companies that ultimately answer to their shareholders. Blaming them for trying to return the biggest profit they can is silly. Do you blame Apple or Samsung or General Electric for the same thing? They are all in the same business - making money for their shareholders.
As for the system limiting competition, I'm not quite sure what you are talking about. There are 5 large, full service banks in Canada but there is nothing I am aware of stopping another from rising. In every significant aspect of their business they also have competition outside of the "big five"... for deposits there are tons of credit unions, that also give personal loans, credit cards, mortgages, etc. Lots of mortgage brokers and credit card issuers as well.
Banks are not crown corps - they are actually one of the most heavily regulated businesses (both here and in the US). In fact, the giants in banking like Bank of America, Chase, etc are having a hard time operating in the US because turning a profit has suddenly been deemed a bad thing.
The regulations in the US have increased to ensure the mortgage meltdown doesn't happen again......they might cry that it is stopping them from making a profit, but it is in the best interest of the economy in general.
Credit card issuers seem to use banks, or operations like Chase to back them. Sears for instance, uses Chase. Mortgage brokers negotiate mortgages with banks, or private lenders.