Bit conservation! The redesign makes more sense now.
The old logo uses a complicated serif font which can only be created using bezier curves. All together, it has 100 anchor points, resulting in a 6 KB (6,380 bytes) file. When compressed, the size comes down to 2 KB (2,145 bytes).
A simplified version of the new logo, on the other hand, can be constructed almost entirely from circles and rectangles (with the exception of the lower-case g).