My daughter Eva is nearly 7 months old. We had a terrible time with her sleep. She is medicated for reflux and has been diagnosed by her immunologist as intolerant to cows milk protein. Before we worked that out my milk was upsetting her. I've done and do everything you are not "supposed" to do, rocking her to sleep, feeding her to sleep (most nights), driving, pram.. All of it.
Five months came and still no waking hourly, we had a couple of weeks of hell around that age but she gradually got better. Now she is either sleeping through or waking up for one feed most nights, barring the odd random bad night. She's only 6kg so feeding overnight once jf needed is perfectly reasonable. I don't thin it proves or disproves anything but there it is. I think a lot has to do with their personalities.