Why did CN not buy KCS?

Could you please elaborate on the reasons why CN decided not to purchase KCS? Was it due to financial constraints, strategic considerations, or perhaps some other factors? It seems like a potential opportunity missed, so I'm quite curious about the decision-making process behind it. Did CN conduct a thorough analysis before making this choice? If so, what were the key findings that led to this decision? It would be great if you could provide some insights into this matter. Thank you in advance for your explanation.