UPS and FedEx charge more because they generally provide more -- faster service, door-to-door delivery (no third parties, no hand-off between USPS and Canada Post, etc), and significantly better online tracking.
For occasional shippers, FedEx and UPS can definitely be expensive... but for regular, volume shippers, you can negotiate for better rates based on your volume. It's how many companies can afford to overnight seemingly everything they ship -- they do such a large volume that they can get
significant discounts on the shipping costs.
As to the Customs duties/taxes - you pay more for FedEx and UPS because they use their own brokers, eliminating the 'stall' at Customs. And since FedEx employees are not unionized, there's not fear of "labor disputes" slowing things down either.

Express carriers are not for everyone or everything... but they should not be dismissed out-of-hand. When a customer needs something badly enough, express carriers, with date-specific delivery guarantees and years of on-time performance history, can be just the thing.
-Bob.

V.46 Trading Assistant, since 1997!
"Assume Less, Listen More, Share Freely, Enjoy Fully."