The amount of time parents spend with their children is certainly a factor in the well-rounded upbringing of a child, but it is a poor metric by itself. Children need parental involvement, parental accountability and discipline, and good parental examples to follow. If the latter two are lacking, the first is largely irrelevant.
Agreed with the proviso that it's not just "with" but "caring for". You can be with them and not engaging in any way. You can be caring for them without being directly engaged with them (eg supervising a playpark visit).
