I noticed this a few years back but wasn't sure why it was done. Its been several years since I've actually turned a wrench on a racecar and even more on a sprint.

When and why did they change front hubs to the bolt pattern vs the knock off?

I also noticed that many wheels are two or three pieces now. Is that so that the rim can be changed out vs the entire wheel?

Sounds like a stupid question, But I'd like a informed answer.
Thanks
Chuck