"Nobody ever got fired for X" is a rhetorical device which means "in most situations, you generally won't be faulted going with the most main-stream option on the market".
To be fair, as frustrating as it is sometimes for those of us who want to use the best tool, for those who have jobs affected by the risk in their decisions, it's a sound principle to default to.
Nobody ever got fired for choosing standard browser technologies, I would have thought :-) Which, from your list, would include canvas, webgl, wasm, and workers. As for the rest — they may very well have been :-)
Well, there are a lot of abstractions over those. Canvas by itself in the raw isn't very useful without a framework on top of it. Same for the others, except maybe Workers...
