Yeah I think the keyword is "design" meaning plastic parts have replaced fundamental upgrades around the blocks/hubs/plates which could potentially cost way more money to buy those separately than buying the kit standalone :(
You can't come close to $629 for the RTR which is based on the 2.0
https://www.horizonhobby.com/product/8ight-xe-electric-rtr-1-8-4wd-buggy/LOS04018.html
Yet the 2.0 kit is $750:
https://www.horizonhobby.com/product/1-8-8ight-x-e-2.0-combo-4x4-nitro-electric-race-buggy-kit/TLR04012.html
I'd...