You'll find that men's shoes in the 17th and much of the 18th centuries often do have a "heel". It's not, of course, the stiletto style we find in women's shoes today. Usually made of stacked leather, though occasionally of covered wood, this style first caught on because it helped with riding horses, arriving from the region of Persia. The heel in general goes out of fashion in the late 18th century, not just for men. Women's heels shrink very small by the 1790s and are almost never seen after 1820 (until the 1860s and onwards). Generally I'm loathe to link to something like a news site, but Elizabeth Semmelhack is an expert source in shoes, so her interview on the topic is very useful. Just remember, in reality, men's non-sporting shoes still have heels today, they're just very low.