It's also bullshit. For a weapon this age, there are no patents, and parts can and are supplied by a multitude of vendors. The number of vendors that specialize on supplying parts for firearms that are no longer produced is quite high.
What I see is an unfounded belief that buying long-term non-OEM support will be more expensive than buying support for a new weapon. In the real world, it's the other way around - new weapons are far more expensive to support. Never mind all the other costs of switching.
Mark my words: Five years from now, there are going to be Canadian news articles about how the original budget was blown several times over.
My guess: Someone has been promised kickbacks and incentives, and the choice of a replacement has already been made. It will now be followed by a circus to "determine" that it's the best choice. And it will end up costing the tax payers a fortune. I.e. a smaller version of the F-35 scam. Follow the money trail.