For most people, starting a web host is really bad for a few reasons, such as;
1. The general public are not tech savvy at all, leading to you having to answer questions that are super basic, like how to install WordPress.
2. A lot of spammers will likely sign up for your service, leading to you spending a lot of your day tracking down which user has been abusing your service.
3. In order to compete with other web hosts, you have two choices; you can advertise your service as "noob" friendly and have to compete with the likes of Hostgator or you have to undercut everyone and likely have to live on below minimum wage.