I think there's a distinction to be made between taxes such as GST/VAT and supplier fees. I think it is bunk that NAVCanada, airport and security fees are applied to tickets separately - they are a cost of business and SHOULD be levied equally irrespective of airline and preferably included in the ticket price. What passengers find in reality is that what are considered fees vary wildly between airlines operating on the same routes and it is verging on impossible to make easy comparisons (especially for those airlines which don't post tickets on sites like Expedia such as R***air)
We're all used to pulling up to a petrol station having seen the price posted on the side of the road. It would not be acceptable for the price to be 50% more than posted, yet that is the reality of reading posted fares on BA.com and then attempting to book them.
(@ Hartington - petrol stations in Canada produce a piechart of how much they get from a litre vs various levels of govt, producers, refiners etc - airlines are more than welcome to do this of course but the headline price should conform to what the traveller will pay)