Looking up names like Steele and others with the e at the end reveals that before anything was standardized, there were many variations of every name, just as there were for every word. And that they still exist.
Changes in spelling of names, as well as words, were effected by all of English's transformations, as well as its influences from many other languages.
In the Middle Ages, for example, names like Steele could've been written as Steile, Steel, etc. depending on who was writing it. Whoever wrote at the time would spell things whichever way they heard them, and they may as well have all heard them differently.
Checking out this page (of questionable reliability) shows that spelling someone's name the same way during their entire lifetime is a more modern idea, and even names like Shakespeare were spelled differently (Shakespere, Shakespear, Shakspere, Shaxpere).
To answer your question, I think the fact that the "English word" currently doesn't have an e at the end means that that's just the variation of the word that stuck. You'll see people with the name Steele now, but, for example, one of my professors is named Steel because that's the name that ended up sticking. Or, who knows, maybe it was just spelled that way on a passenger manifest when his family traveled across the ocean for simplicity.