I believe overall Inflation between 2020 - 2025 is 20 percent aprox. Sooo no
More likely several factors have a much bigger impact.
1. One year delay
2. High intrest rate environment
3. Inflation
4. Classic underestimating costs to sell the project. Ie. The project was always going to cost much more but cook the books until you have to reveal the real costs.
How the hell the above doubles costs...lord only knows. Metrolinx certainly wont tell us.
I find the initial estimates disgusting....doubling those estimates seems insane. But when they package 30 years of operation into the total costs, numbers will always look big.