Well for starters, it was pretty expensive. Any stargate that they could build with household or conventional materials hogged a ton of energy, and was pretty unstable. Building stargates would be super expensive from both a materials and energy standpoint, as well as from a training standpoint, as you would need engineers and scientists working on it to make sure it is absolutely as safe as the Ancient stargates, plus, there wasn't really a need. Why make your own, more dangerous gates, when the Ancients left tens of thousands, perhaps hundreds of thousands of gates basically everywhere? It would just be needless strain on Tau'ri resources.