Are there bad business ideas and niches?

I would like to create content about coaching and goal setting, but don’t want to coach. I love self-help and envision a website that curates resources for those interested in personal growth. My husband thinks it’s a bad idea and it will be hard to make money because there are already so many sites like that.

My question is are there bad business ideas or is it just about believing and taking the right action? Should I be more practical and find something that has more potential? I ask because there have been times when Brooke mentions that some niches are better than others, so I know it’s not just about thoughts.