My understanding is that "survival" words in a language like numbers and days of the week are usually taught first, even though they may have a lower frequency than certain frequency used words like "politics" or President.
What makes a word urgent or essential? Could it be that it travels in a "group" of words, some of which are essential? For instance, the word "hundred" is a less-common word in many languages, but it is found under the heading of numbers, such as "one," which is essential. Then, would the less common word "hundred" be taught in the same batch as the much more common "one?"
Is is because frequency tables are (mostly) based on written text, which differs from spoken texts? And are even "oral" frequency tables derived from movies or TV shows likely to be different from every day speech?
Or could it be that words like "politics" or "President" are found frequently, particularly in texts, because they are "international" words, even though they are less essential than "day to day" words? Which means that the introduction of the "common" words is pushed back later than the essential words?