Part of being a good dev is knowing which tool to use (and when to not use a tool) and how to get the most out of the tool.
I don't think that it's very economical to provide smaller instances than that for most cloud hosts out there.
The WordPress download is 20MB compressed, 63MB uncompressed, containing almost half a million lines of PHP spread across over a thousand files (~16MB; around 55% code, the remainder blank or comments), over half a million lines of JavaScript in over 500 files (~25MB; around 67% code), a couple of hundred thousand of CSS in 700 files (~7.5MB; around 75% code), and the odd spot of other languages. (This is in languages where more code fairly directly means slower, even if faster code can claw that back; whereas in compiled languages, more code just means slower compilation, and runtime performance is comparatively uncorrelated.)
That’s not particularly lightweight.
Conceptually WordPress isn’t lightweight, either. I’ve never used WordPress myself, but I’ve seen three people using it, and in each case they were being drowned in choices and data fields, using two or three fields out of the thirty or more fields it was shoving in their faces; and the themes and plugins and such made matters considerably worse and more complex; and a lot of that complexity didn’t seem well-structured, though my observation has only ever been brief.