Think of it as an advisory panel to the Church. I'm sure that parts of the Canon can be found adopted by later formal Ecumenical Councils, but there was sufficient heterodoxy in it that was rejected.
Once again the Catholic pick and choose which creeds and doctrines they will believe in. Those Trent people were soooooo much smarter 800 years later than the heretics like Augustine and Jerome.
One has to wonder why they even bother writing it down. After all, paper was hard to come by.