I kind of agree with you but I don't think Silva's absence made that much difference. No doubt he held the defence together pretty well in previous games and organised team mates playing in the right positions defensively. Virtually all 7 goals conceded were as a result of defensive errors but even with his presence, the best Brazil could have hoped for would have been a 1-0 or 2-0 defeat I think.
Neymar's absence was irrelevant. When your back line concedes 5 goals by half-time no striker (however world class he is) is ever gonna make a difference.