(Also, I wouldn't say `awk` or even `grep` are good examples (as the OP admits) -- they were definitely chosen for whimsky, with, if not actually backronyms, still acronyms deisgned for whimsy).
And another part of it is that so many people now have dreams of commercializing their product, so you need a "brand" name. (I guarantee the namers of the tools had no designs on commecializing grep or awk). (I have little sympathy for this one, but it's the world).
I do agree with OP it is a problem for accessibility. Newcomers who haven't already memorized the mangagerie have a lot to figure out; some people's brains work differently than others and it's easier or harder for some people to remember these arbitrary names naturally; I'd guess it can be especially hard for non-native English speakers, but maybe it's all Greek (ha!) to them anyway, so.
When i have tried to name things plain though, I often have trouble -- we want something clear, but also relatively short (especially if it's going to be in namespace or other identifier names and be typed a lot!) -- and not already taken in popular consciousness or the package managers we'll need etc, and often I have trouble finding such!