Sometimes (only sometimes) Marxism can't explain things. Here's one. Material conditions determine everything. But do they? Take these two types of material conditions:
1) When I was in my early 20s, I was a refugee, moving from one small apartment to another with my impoverished family. I was attending Belgrade University and later the Center for Women's Studies and most of my meals consisted of a slice of bread with some kind of a spread on it, usually jam. (A slice of a real loaf, granted, not the wonder bread nonsense.) I couldn't travel--I had no money and no legitimate passport. I had no job other than occasional tutoring.
2) Now, in my late 30s, I can afford a small apartment in Chicago where I live with only one person, my husband. We have enough food, sometimes we even eat out or order in. I can't travel outside of the US at the moment, but soon enough I will be. Meanwhile, I fly to a different US city for an academic conference about twice a year now. I have a brand new Ph.D. Some say that, as a grad student, I lived below poverty line, but compared to my early 20s (and late teens and mid and late 20s as well), I am rich. In the fall, I'll have my very first full-time college-teaching job.
Despite these two sets of contrasting material conditions, my creative process is much the same. Ideas for and realizations of poems, songs, and prose pieces come to me in waves, and the content is not that radically different either. Yet the world is a different place in many ways now. (That's why you also always need some Freud along with your Marx.)
Of course, I'm pushing this critique of the Marxist theory merely as a stylistic/rhetorical trick. Ta-daaa!
But the point is that certain things do influence your creative process much more than the relative poverty/riches you live in. Basically, it boils down to time. If your workload is more than full time, and plus you're a parent, you simply don't have the time (I imagine) for ideas to pop up, brew, and get realized.
Here's what a writer friend I've known since our early-to-mid 20s, whose free time is very limited, has just started: http://simplecreativeyear.wordpress.com/ She will spend 5 minutes each day doing something simple and creative and she'll document it on her blog. It's her gift to herself for her 38th birthday, but she might not realize that it's also her gift to all of her friends and admirers. Happy birthday, and good luck, KS!