407ETR tolls will always outpace inflation because they have to account for:
- Staff salaries (cost of living adjustments for inflation)
- Constant widening means more area to maintain
- Constant population and employment growth along the highway and outskirts of GTA
- Constant toll increases to combat congestion on sections that already fully widened (410 t0 404)
All these combined mean that things are only going to get much more expensive. This is why the 407 transitway is good long term planning. The preliminary designs are mostly complete for the busiest sections of 407:
http://www.407transitway.com/
I suspect the construction ball will get rolling when tolls hit $1 per km (probably in 10-15 years) and will be completed by the time we hit $2/km tolls.