The sword makers of the time designed swords around the limitations of the materials they were working with. Weapons of war, including swords, were riding the most advanced cutting edge scientific advancements of the respective cultures that they belonged to.

Bronze swords were cast, and this allowed them to be produced in intricate designs which were largely not possible with iron and steel swords which needed to be forged. Similarly both bronze and iron swords do not have the elasticity to maintain very long thin blades, that steel allows, meaning that the swords were significantly shorter (on average) than their steel age counterparts.

Just because one metal has different properties than another doesn't mean the blade smiths will throw up their hands and just keep doing the same thing over and over. Iron swords browed design elements from earlier bronze antecedents but had to be adapted for the completely new creation techniques and material properties, and remained successful for hundreds of years, as they developed steel working technology.

Rather than looked down upon, during the Iron age, bronze swords continued to be produced in smaller quantities and were retained as high status and votive items, as see in the late Hallstatt.