Is Black really that much (or at all?) ahead in terms of development and piece activity?
Just counting, there are three minor pieces developed on each side, plus the White queen, while Black is to move and can castle. Pretty equal.
Black's three minor pieces surely are active at the moment, but are White's much worse? I don't think so.
Most importantly though, if we look a little bit ahead, White has much more straightforward moves to improve his position. A direct a3 will more or less force Bxc3, obtaining the bishop pair for White (with one of them on an open long diagonal to boot). The Nc5 is then in danger of being chased away by b4. Black can answer ...a5 or ...f5 (supporting e4 as a new outpost), but both moves create new slight weaknesses in a pawn structure that is already slightly weakened by trading away the "good" bishop.
Black cannot do much against moves like e3, Be2, 0-0 or Td1, either. Not breathtaking, but all very solid and natural. Meanwhile, Black's main break ...d5 is not without danger (for example, if it's played too soon after the exchange on c3, White may discover an attack on the loose Nc5 by cxd5 and Bxg7, netting a pawn).
I won't claim that White in turn has a real "advantage". If Black plays well, the game will still be about equal. But I'd actually prefer to play White.