Web hosting can be purchased on the occasional sale, such as Black Friday, so renewal costs can be much higher. I always compare renewal costs and not the initial loss leader signup cost. The 2.7 times higher hosting costs may be valid, depending on the hosting services provided. Moe importantly, what did you buy? Some hosts don't even provide on demand backup, and some hosts will charge you for a restore. Some hosts don't provide SSH. Shared services or a dedicated IP? Reputation, which is very important?
I would not recommend self-hosting at home. There are too many rogue bots roaming around the world, and the possibility of hacking is near certain. Yes, if you keep up with all the updates and monitor your server carefully you can be ok, but I know that my hosting provider had to purchase additional software just to deal with DDOS attacks and other intrusions. Unless you want to take on the sys admin role, for me the hosting costs are well worthwhile. If you are with the right host, your site becomes more popular and you run out of ram it should be easy to upgrade.
Personally I'd rather concentrate on the web site, SEO and social media than futz with Apache settings, so would rather be on a host provider. The hosting costs can be pretty small, depending on what you purchase.
Don