[quote=Halvtand]
I’ve been roleplaying for quite some time and in that time I’ve noticed a trend. 
Elves are among the most popular races to play, with the familiar human running for second place. Dwarves are among the most unpopular, and I’ve seen people asking to play as an orc or other “minority”-race rather than playing as a dwarf.
[/quote]

Short, stocky, pig-headed, irrational people don't like to be reminded of themselves. 

In seriousness, dwarves are the more flawed, more human but inhuman, less fantastical option. They don't have the easy familiarity of "me" to players (humans), but have the extreme virtues and flaws associated with people (greed and jealousy, blind loyalty, distrust of outsiders, stubbornness). Nor do they have the escapist power appeal of elves, who are more magically inclined, attractive, and overall better, often with the biggest flaw being they're too thin and apathetic to the inferior people.

One has to offer something of value to the average player. An advantage, or a novelty. If you made the dwarves cool, or necessary and important, or the cryptic last of their kind, players will eat that shit up. Dwarves have the appeal of being more grounded, less alienated, but they have to be given some credit or attention in the lore. If it's negative stereotypes with nothing to fill and compensate the paper-thin culture and characterization, only atypical players(or players wanting bad characters) will go for them.