If you can point to an episode of Voyager where a DSSV fights and loses to an Intrepid I might agree with you. But then I like Star Trek and its canon - even though it doesn't always make sense.
Neither the Imperial nor the Avenger show up in any episodes, and yet it's been very well established that the Lakota, because of what it does in one episode of DS9 is absolutely supposed to be superior to those much newer ships.
So, applying that exact same logic, the Intrepid (which has 7 full seasons of canon to demonstrate how superior it is) must be superior to the DSSV.
It's Cryptic logic and it's how the tier system is supposed to work.