Why some electrolytic capacitors have a bigger distance between their two legs?
Every year they seem to figure out ways of making e-caps smaller and smaller so at some point forming the leads is required to fit the pattern of the old capacitors. 

Changing hole layout of high volume inexpensive boards can involve changing hard tooling (punch positions in the die) rather than the soft changes that are typical for low-volume and high-end boards. 

The suppliers can provide parts on tape with the leads formed to the customer's requirements.