For this writer, it's more of a case of being abducted by an idea, a mental image, or even just a single word. For me, there is a click, "You will now write ... " and I obey.
This works well, as I have sited before, when I can stop what I'm doing and write, at least, a memo for later reference, but when I have to put it off, it relentlessly teases.
My muse tends towards impatience, however, and when I have held off from complying for a tad too long, that which I was to write evaporates.
I cannot assume that this is so for other writers, but once I focus on "it," all else bleeds away to the very edges of my mind, and I become a willing captive.
So, I would have to say that my writing is not a vehicle of escapism. Instead, I would call it a portal to an alternative, autonomous reality.
And it is a very communal one. Despite how I may appear to outsiders while thus engaged, I am most positively not alone in this writer's realm.
My muse is ever present here, occupying me with all manner of oblique intangibles, which I become obsessively driven to collate into proper form.
There is nothing else quite like having access to such an expansive, creative, and fulfilling cosmos as this. I do not escape to writing; I am seduced by it.