anothernumber I was also thinking about this thread in the wee small hours (up trying to comfort 12mo DS3, who has tonsillitis for the third time in his little life
). Of course you need to consider the whole picture. My Ds2 was a brilliant sleeper as a baby, but now at 4yo is very prone to night terrors due to an overactive imagination, bless him. DS1 never did the night terrors but had chronic separation anxiety at 1yo, which DS2 never did.
Different children, different issues. But I still maintain that parents can influence how well their babies sleep. Not guarantee them sleeping through. But influence it. In the same way that they can influence how well they eat, even if a lot is also dependent on the nature of that child.
The thing is, there is a world of difference in what babies will do, at different ages, and of course it is great that posters come on to reassure parents that not all babies sleep through at certain ages etc etc. Where it becomes unhelpful, IMO, is say when a parent posts in desperation because their 8mo is waking hourly through the night and has to breastfeed back to sleep, asking for tips on how to help, and is told over and over 'oh that's normal, just co sleep!'. And when it is implied that any sleep training is wrong, and cruel, etc etc. I always feel so sorry for the poor posters in these scenarios but know there is no point trying to post any alternative suggestions because the 'oh it's normal' crew will shoot you down in flames and say that all sleep training is evil.
And in that scenario - the thing is that an 8mo who can generally settle themselves to sleep, can also resettle themselves when they stir in the night, but perhaps wakes a couple of times in the night for a feed = absolutely normal and will sleep through when good and ready to drop those feeds.
An 8mo who can only fall asleep with a breast/dummy in their mouth, or when rocked/cuddled to sleep, who then wakes up hourly through the night = would probably sleep better if parents tried some different techniques. Might not sleep through, sure. But would almost certainly wake less.
Not, however, according to the MN 'it's all luck' crew.