As life rules not always becomes valid - size matters. There are a bunch of service providers offering VPS ( virtual private servers ) for cheap money. The market adjusted to a few offers which turned out as minimum requirement. Years ago most of websites where programed static in html and the cpu/ram requirements haven't been that high. Nowadays you are ages behind if you don't know what the shortcut CMS stands for.
Good and flexible Content Management Systems do need a database in backend and latest php version. This consumes resources - remember this. In my opinion a VPS with less than 1GB RAM and 2 cpus don't run smooth enough. This website is build on a 1GRAM/1CPU/20GDisk and db-rebuild or cache-clear takes atleast too much time!! But hey I'm on typo3 using a lot of pictures converted by imagemagick.
I will do compare two categories.
An Admin wants to record his/her howtos and thisfore the need of a wiki or reporting system is mandatory. The amount of users which are connecting to this wiki is possibly small and the usage of pictures is almost zero. So most of his/her online documentation is text-only - written in markup language.
The Designer wants to share his/her goods with public as presentable as possible. A lot of pictures a lot of multimedia with a complicated and well responsive web-template. We assume that his/her market is small so we don't need HA Proxies or Load Balance because it is just a local market. But the multimedia and templating aspect affords some more power and the pictures do need space to store them.