I think one of the problems is one of marketing.
The hackers of the 60s wouldn't have cared but there must be a number of people and businesses since who have been put off, consciously or unconsciously, by the language having the same name as a speech impediment.
I'm being entirely serious; I think the language would have been more popular with a cooler name.
Another problem is a perception of Lisp as being an old language. When I tell work colleagues about how great Lisp is, they're put off by it having been around a long time. I tell them that's ridiculous, the /computer/ has been around a long time, should we abandon that? But it is an uphill struggle.