I'm not sure the "three types of babies" thing really works. There are lots of types of babies. I think TulipOHare has it right about being long periods of sleep being a developmental stage, like walking or talking - and likewise probably related to all sorts of individual things, physiological and cognitive and developmental, like the baby's muscle tone, temperament and digestive motility (yes, there is a huge normal range in the time it takes for the gut to empty, whether in babies or adults - hence why the frequency of baby (or adult!) pooing is so wide!) Despite generalised HV-style folk wisdom, some babies do need a feed during the night longe than others do - perhaps their gut simply empties quicker. It's well known that bf babies' guts empty quicker compared to ff babies, so they tend to wake more often.
OP are you sure most of the difference isn't just in knowing people who mostly ff rather than bf? The whole way you practice so-called "sleep hygiene" is different if you are EBF or extended BFing. Nearly everyone I know breastfeeds and cosleeps, so clearly it depends on your circle. Most mothers and fathers I know are mid-late thirties or early forties, work (normally flexibly), do attachment parenting, don't wean until 6mo, share childcare equally between mum and dad, and talk endlessly about how their baby doesn't sleep through the night. It's definitely not thought of as normal for an 8mo to "sleep through".
My DD wasn't a "bad sleeper". She slept great: she just didn't sleep for a long period without waking up for a quick feed and resettling, which is a very different thing an totally normal, physiologically, for a breastfed 8mo. FWIW she had/has an excellent "routine", and will sleep for a 12hr block overnight 8-8 like clockwork - but until 12m she also woke up every 3hrs for a feed, from birth and also like clockwork. She wasn't crying or distressed, just a bit hungry, and would feed back to sleep happily. I'm not sure what I could have done to make her not need those feeds! On turning 1 she has just suddenly started sleeping for periods of 8hrs+ without waking. I think I would have caused myself a lot of fuss and heartache trying to force her to change something that she was going to outgrow naturally anyway. (Leaving DD to cry even for a short period produced meltdown - she is not one of those babies who will grizzle then stop. She works herself up into hysterics. CC or CIO would not have worked.) DD was also a baby who did not sleep much in the day - from about 2months you could get at most two 30-min naps out of her. Nothing kept her asleep longer. But she is probably not temperamentally a sleepy baby - she has always been very lively: strong muscle tone from birth (trying to lift head right from birth), loads of energy, sat and walked early, beady eyes following everything - she was just a bit hyper during the day and not keen on sleeping. That's just how she is. I couldn't have made her nap more, or stop waking every 3hrs in the night to eat, any more than it was somehow some achievement of mine that she had unusually strong neck muscles at birth. That's how she came!
Anyway, why is there this ingrained cultural assumption that not "sleeping through" without waking is "poor" or "bad" sleeping? As others on the thread have pointed out, tiny babies are designed to wake up every few hours to feed and to wake you up. This is so they don't die. Routines, sleep training and "sleep hygiene" are ways of managing and overriding this to make it fit our desires and lives. Not many people on the thread have mentioned SIDS, but it's worth saying again: the main risk period for SIDS is up until 6 months (but it's not risk-free after), hence the recommendation for babies not to sleep alone until then (and 8mo is not that much older than 6mo). And waking frequently in the night is a physiological protection for the baby; it's known to be a risk factor for SIDS for a baby to sleep too long without arousal out of a deep sleep state. In that context, "good" sleeping looks very different: it isn't a flaw in the baby that it wakes in the night; it's what it is meant to do, and different babies grow out of that physiological stage at different times and rates. Ultimately yes I was tired, but I was actually quite reassured that my DD woke regularly: it meant that she was doing what healthy babies routinely do.