Let's stipulate that the presence of the CBC in a market can discourage new entrants and weaken existing market participants. Does this constitute 'meddling' with the market? Only if we agree that
a) there is no market failure in the journalism trade, and
b) news is more like a commodity (ketchup, say) and less like a matter of public interest (pensions, say).
Both contentions are questionable.
On a) I tend to think that the fact that established news vehicles are shedding jobs and losing share value says that we can't rely on the existing market to ensure that Canadians have equal access to news.
On b) I tend to think that news and public-affairs analysis is a prerequisite for democratic governance, and that there is a role for a public journal, a role played by the CBC in Canada. I'm sure that if we abolished RRSPs tomorrow people would be able to fund their retirements through private financial vehicles, but the fact that such vehicles do exist doesn't constitute an argument for the government to vacate the business of retirement planning.
The issues you raise are good ones, but I think you need more space to work them out.