It's hard enough to get anything timely going in these Dragon setups anyway. It always feels like your behind. So if one gives the opponent another tempo or two, Space might be only a minor worry. Mate or major material loss is probably likely. Think the same is shown in the earlier mentioned Larsen - Petrosian 1966 game.

Reshevsky also seems to fall behind and is punished in this nice win by Fischer:

I would disagree. Compare the number of pieces developed after each of these moves:

Move White Black
1 0 0
2 1 0
3 1 1
4 1 1
5 1 1
6 1 2
7 2 2
8 3 2
9 3 3
10 4 3
11 5 3
12 6 4
13 6 4
14 6 5
15 6 5
16 6 5
17 6 6
18 6 6
19 6 6
20 6 5

So only twice in the first 20 moves did Black have 2 less pieces developed than White, and after 20 moves he only had 1 less piece developed than White.

Now look at the position after 20...Qd8:

click for larger view

White has 2 pieces and 1 P on the 5th rank and 2 pawns on the 4th rank. Black doesn't have any piece or pawn beyond the 3rd rank. And with respect to mobility White's pieces (excluding pawns) have 30 possible squares to move to, and Black's pieces have 25.

Therefore after 20 moves the difference between White's and Black's developed pieces is only 1 in White's favor. So it doesn't seem to me that Black has wasted too many tempi in development through move 20, at least compared to White. Yet White has a commanding space and mobility advantage, 5 pieces and pawns on the 4th rank and beyond compared to none for Black, and 30 possible moves by its pieces compared to only 25 for Black. And White is attacking 4 pieces or pawns compared to only 3 by Black.