The Created didn't necessarily destroy Human industrial centers outright - although they almost-certainly did brick/scuttle whatever they couldn't capture/hold - but, instead, they hijacked those facilities and held them hostage against Humanity...

Sure, the Guardians were useful for summarily blacking-out entire planets all at once and smaller armigers like the Prometheans were useful for point-enforcement, but the espoused goal of the Created was to eliminate the galaxy's very impetus to rebel; their very motivation to fight...

For the Unggoy - whose fast birthrate and long lifespans had caused them to overpopulate their homeworld even before the Covenant arrived, and whose lack of agency in that organization left them again on the brink of total famine and societal collapse now that it had dissolved - the Pax Cortana was able to win popularity and allegiance simply by providing food and other resources. (This is mentioned in "Bad Blood" as the main reason why the Unggoy Transitional Government sided with the Created and against Humanity; the UNSC - even if it were intact by that point - just wouldn't be able to compete with the scope and tempo of aid being rendered.)

Humanity was very much less-desperate than the Unggoy, however, so a different tact would have been necessary to pacify our species... In fact, almost the exact opposite tact was necessary; restricting our access to resources rather than expanding it; taking away the things we would need in order to (want to) fight...

Humans cannot go for very long without food (especially if they are physically exerting themselves through hard work or combat) and very few - if any - Humans would willingly march into war completely unarmed (especially against a technologically-superior foe), and so the Created would have seized Humanity's factories and farms to cut off our ability to make and get weapons and equipment and rations...

These assessments of Humanity's willingness to fight go out the window when we become desperate, however; when we judge that there's nothing more we can lose in the attempt to better our circumstances. Someone who's already starving and destitute will fight ferociously - even if barehanded - if they hope they might get a meal or some other comfort out of victory, and only have to fear an end to their suffering out of defeat...

In order to tame Humanity, then, the Created would have had to strike a careful balance. Production of weapons and military gear would have been halted outright, but everything else - food, clothing, electronics, etc. - would simply have been scaled back or tithed. The factories and farms would keep operating, but their outputs would be reduced or had massive bites taken out of them so that there was only enough to meet the local population's most basic needs/standards for living.

Now not only did they lack the things they'd need to fight, but they had something - a relatively-acceptable quality of life - to fear losing if they tried to fight anyway.