yeah as ticktoc said, if u had so many dreads the AI would have a lot of quanta upgrades.
u can also check in the score screen, scroll across to the economy page i think it is. it will show u how much quanta was invested, and u can work out (+/-) from that what level the enemy was on.
i develop dreads quite quickly, and by the time i have 4 dreads, im surely on higher than 4/3.. the promethius alone should have contested the enemy hyperion at least. if u were on similar quanta investments.
also as ticktoc said, barragers suck with dps, they are basically walls, their dps is VERY low. rather build the actual anti dread defence guns(sentinels), they rip dreads apaart, u dont even need to upgrade them. also maybe try heras, they might help ur dreads.. and u can never go wrong with medics, they will help keep even ur buildings alive, u can safely spam medics.. (until they get nerfed)