It is, and being aware of that is crucial in having the right perspective on inventors (and same is true about scientific discoveries). That is, they're not some superhuman geniuses so far ahead the rest of humanity, that through sheer power of their minds, they can wrestle breakthroughs from the hands of gods. No, they're just specialists who were at the right time and place, and had the right experience, to be the first to pluck an invention that was already ripe for the taking.

This isn't to diminish the value of inventors. Even as all discoveries are tiny increments on top of prior work, so tiny they quickly become apparent to many people in a given field, it still takes exceptional skills, knowledge and smarts to be the first (or one of the firsts) to make that increment. That is worthy of respect. But at the same time, inventors are not critical to inventions - if not for the inventor we know, someone else would've done the same within months or years.