I'm pretty skeptical of Martha & David Kimmel's theory, actually, because it seems to totally ignore the fact that breastfed babies get taste variation from birth via mothers' breastmilk!
If a baby is exclusively fed infant formula, then yes, I'd say they eat for hunger not for taste because the taste is completely uniform, never varying (unless the parents are switching among different formulas, which isn't typical).
But I think it's a totally different story if a baby is getting mother's breastmilk, which is a dynamic, living fluid! We know that proteins from what mom eats can pass through into mother's milk, which strongly suggests that flavor would be present too. There are also studies that show that flavors of what the mother eats are somewhat shared via mother's milk - one study in particular even showed that babies stayed longer at the breast in the study group who was ingesting increased levels of garlic (vs the control group who were eating low garlic).
Also, any mother who has pumped breastmilk for her baby over time (like a mom who returns back to work and provide breastmilk, or a mom who is exclusively pumping for her baby) has noticed that breastmilk varies from day to day in color/shading. Wouldn't surprise me if that affected the taste as well.
So, in the end, I think the authors of the Mommy Made book are not telling the whole story because they are probably not taking into account breastfed babies who get dynamic, living breastmilk -- and it would make sense that this wide variation of tastes from birth would positively impact a baby's transition to solids. Sounds like the Kimmels are only focusing on those babies getting infant formula.
As far as babies growing into toddlers and beyond, of course other factors come into play in terms of pickiness, etc.! Certainly, I think the behavior the parents model for the child have a significant impact - for example, if the parents themselves are picky, or if the parents are adventurous eaters. Additionally, as another mom already mentioned, a young child may well know intrinsically to avoid a certain food if it makes them feel bad (food allergy or sensitivity).
Also, it's important to take into account that sometimes severe pickiness issues are actually sensory or motor problems that the child could get past with the right therapy from a feeding specialist (for example) and excellent family support.
And last but not least, sometimes food issues are really just toddlers or preschoolers flexing/experimenting with their autonomy. :)
So, lots of factors come together to make up a child's willingness (or not) to try and eat a variety of foods, IMO.