The installation guide for self-hosted Ghost assumes that you have at least a virtual private server, and gives you a bunch of commands to type into a root shell. By that time, you've already lost 90% of the people who would have chosen WordPress.
Its written in node js though right? You can run php and mysql almost anywhere you want. Even the most basic hosting setups are pre configured for this. Apache is preinstalled on most cheap shared hosting.
That's the thing.. if you want to take down wordpress it should be something current wordpress users can easily install on their current hosting with zero extra config to do. No terminals no server settings to deal with.
A wordpress install is literally drag and drop the files onto the server with ftp and open the web address. Enter some details for the mysql dB via a ui and that's it.
After that there are thousands of themes and plugins that let you do anything from ecommerce to a drag and drop blog without much effort.
The "run everywhere" advantage is eroding. These days you can get container based hosting that can run anything for cheap too. It's not quite as easy for the non-technical user yet. But I suspect it will get there.