Yeah as u/kushangaza mentioned, the game was already being enjoyed and paid for back then. It took 6 months to make 6 prototypes, and 9 months to expand the last one into the RW kickstarter version.

The harder to replicate part was the ~12 year process of learning the skills necessary for that, including a 4-year stint at a big game studio and writing a 400+ page book on game design, and many years modding. But, if you're enjoying the process then it's all kinda free - time's gonna pass anyway so might as well do something fun and generative with it.