Dogs and coyotes and raccoons can rip apart even the 1/2" chickenwire.
Honestly, you don't KNOW whether a predator problem "didn't materialize" (yet!) or whether things DID come sniffin' round your coop and just were unable to get in. The whole problem is that the only thing you will ever be CERTAIN of is if a predator gets into your coop and eats your chickens. If nothing happens, it could be that nothing is around (ha) or that nothing can get in, but it can also very very easily be that nothing happens to have TRIED YET. Browse the "PRedators and Pests" section of the forum to see allllll the "my chickens got eaten" posts from people who coasted along with everything being fine, despite weebly fencing, for sometimes a rather long time.
If you want to keep your chickens from being eaten, you are really best off with either 1/2" hardwarecloth, or something larger and heavier (stout 1x1 or 2x4 welded wire, or stout chainlink) with 1/2" mesh attached over the bottom 2-3'. If you are going with the latter plan, IMHO it is quite reasonable to use 1/2" chickenwire rather than 1/2" hardwarecloth if that is cheaper and available to you, because you are not trying to use it to keep the whole predator out of the run, just keep chicken heads and predator paws on the correct sides of the fence.
JMHO, good luck, have fun,
Pat