He refuses to hire a team because he does not want to give up control over any aspect of the game, including its development and story. While this might seem like a misguided reason. Since a team would work under his direction. It is important to note he claims that this project is not a job for him. Although, it appears he does not have other employment. Thus, relies on money from his supporters to pay his bills. This game is a passion project. You can not rush a passion project.
Unfortunately, BD seems more focused on enjoying himself at his supporter's expense rather than putting effort into completing the game, It is baffling how long his supporters continue to fund his lifestyle without seeing significant progress. He appears to milk the funds until backers start asking about an update. Then he releases a small update with 300 to 400 renders, promising to meet future deadlines. This cycle repeats endlessly.