The phrase "attaches to" can be a bit loaded in a psychological sense! I thinks it's more of an issue of repertoire, than it is "attachment." Remember- I'm talking about toddlers here- 2-3 years old. We only expect pretend play to be emerging around 2 years old. The child does not yet know how to use language in play, and thus is somewhat restricted to non-language-based (e.g., a focus on the stuff for what it is, rather than what it represents). This leads to relatively quick movement between objects or to relatively less brief attention to paid to caregiver directed language-based play. This in turn is interpreted as a deficit in attention, when it's actually a deficit in language and pretend play skills.
Ultimately, as
@borne_before alluded to, it's an observation that these children play less with toys and activities that lend themselves to extended, functional, and pretend play. If, through teaching or maturation, the child's language improves and we then see more "attentive" play, it stops looking like an attention issue.