Also certain greetings famously have no reference, like "Helo".
Coming back to picturing words... That's how writing was invented originally. Ideograms were the first symbols invented, eg by the Egyptian. The hieroglyph for "duck" is

Note the little bar next to it. It means "1 duck." It also imply the writer is talking of a real, countable duck, and not some other use if the same hieroglyph.
Because ideograms are inherently limited. You can't really have one sign per concept, there are too many concepts.
And some of them cannot be pictured at all, for instance higher philosophical concepts, i.e. the concept of" idea", or that of "law". This posed a problem to the ancient Egyptians who were trying to write these things down.
The solution them scribes found was to use all these 2 or 3 thousand ideograms they had invented ALSO as phonograms, as coding NOT for the thing represented, but for the sound of the word, i.e. one, two or three syllables, rebus style. So the duck sign now also codes for something else: the sound "sa". It appears most frequently to mean "the son", the human male offspring, likely because in ancient Egyptian, the word for "son" sounded like the word for "duck".
E.g. Son of Ra is written (pretty much everywhere) as: duck of the sun.
And note there is no little bar next to that little duck above under the circle (ideogram for Ra, the Sun), so we're not talking of a literal duck here, and ambiguity is minimized.
Now the scribes could code for the
sound of those words for which they couldn't find a good picture, such as the words "law", they could write them down at last... And with this alteration of the original ideographic system, with this injection of a bit of phonetics, classic hieroglyphics were born. They would ultimately lead to our alphabets.
And this inovation probably happened because certain words cannot be pictured.
Them scribes still needed in their system an ideogram (more precisely, a determinative) for all these high concepts which could not be pictured. They chose the sealed papyrus scroll. Y1 in Gardiner's list
Note the papyrus scroll, placed vertically on the left of the pic. It denotes a "bookish" concept.