Artists are often influenced by others. Or they steal outright ... but only from the best, it is said. Possibly styles are similar simply due to coincidence. The last possibility was probably most likely in the days before decent-quality color reproductions in books and magazines were common, especially for artists widely scattered geographically.
Paintings from three artists having a similar "feel" caught my eye recently, so I thought I'd give you a look and so you can decide for yourself if my conjecture makes sense.
The painters are George Washington Lambert (1873-1930), information
here, an Australian working in London; Saturnino Herrán (1887-1913), information
here, a Mexican painter who spent his short life in that country; and W. Herbert "Buck" Dunton (1878-1936), an American who I wrote about
here.
Not all their paintings featured a strong, solid style, but the ones shown below seem to.
Gallery
Lambert: "The Sonnet" - 1917
He was painting in this style as early as 1907 ("Portrait Group, The Mother"), so priority for this threesome goes to Lambert.
Herrán: "La ofrenda" - 1913
Dunton: "My Children" - 1920
While it is possible that Herrán and Dunton where familiar with Lambert's work, it seems equally possible that they were not. Another possibility is that all three artists were influenced by a fourth, earlier painter. Offhand, I can't think of who that might be. Let me know in comments if you have suggestions.