(My first post here since 2008 ...)
I see my own path to unspeakably bad handwriting in a cluttered mess of undisciplined lettering lessons in early grades, and a lack of care by teachers later on.
I say cluttered because in kindergarten, we learned the classic print lettering. Then D'Nelion in first grade, back to print when I moved to another school district in third grade (where I was corrected from being allowed to use D'Nelion), then into cursive writing in fourth grade. But excepting the occasional large-print 'trace the letters' sheets, there was hardly any attempt at producing decent writing -- merely legibility. This is where the undisciplined aspect comes in. As a point of example, I remember having to write ... something (I specifically do not remember) at some point in the early years of cursive, and the teacher insisting it could not be printed.* I had to ask a classmate how to write a cursive capital G, as at that point I had forgotten. But no worry, as my scrawling was deemed acceptably legible. My work was accepted for that assignment.
Further, there was no opportunity to improve handwriting for those of us with atrocious penmanship. In later grades, we would occasionally be scolded about how an i looked like a dotted e, or the r off an o wasn't distinct enough. But it was typically followed up with, "But as long as it's legible, and I think you didn't miss any letters in the spelling ...."
On top of all this was the home factor. My mother encouraged only ever imitation of her own handwriting, which is no more than a series of loose loops, with an occasional turn-back, dot, or cross to make a letter any different. To this day, I habitually imitate her signature when I sign my own name, without so much as a thought. But the fact that "well" appears a series of nigh identical loops on the page when she writes it was enough to turn me away from any efforts at seeking handwriting improvement at home.
In junior high school (maybe early high school?) I decided to give up cursive writing, and scratched my words in ugly, unpracticed print. This was reinforced when I took introductory drafting as an elective, and we were forced to write all caps at a specific measured size, with no personal embellishment whatsoever. For the first time in my life, my handwriting was legible -- even if by force. This made me happy, though at the time I did not recognize it as giving up, so I continued to not only just print, but to try writing only in capital characters, if only varying size to differentiate height. Not once since 6th grade had I been corrected on my writing style. My printing became nearly illegible in my need for expedience, but I just went with it, convinced there was no hope for regularity and legibility in any other option.
As an adult, I didn't even think much about my penmanship for years. And then I tried -- even after joining here -- the easy approach (which I think is another major problem: people are less willing to seek time and effort, rather opting for a quick fix and settling for disappointing results).
But I have run far afield of a point: Things have become lazy in education, and at home. In many areas I have seen parents happy when they can recognize what their child was tryign to write. Schools don't enforce writing drills so much. And one unmentioned point is typing is so taken for granted, than the ability to write is not much considered.
As much as I would have hated it back then, I now regret not having to write pages of repeated shapes until they were correct, then encorporated those shapes into letters, and repeating until it was correct, and so-on. I regret not having to slowly and carefully re-write certain areas of difficulty in my single-digit years until my Rs were crisp, my Ts and Is were differentiated, and I knew enough of the correct way to develop my own hand beyond that point, rather than being left with an untrained hand as my mark.
*Firstly, it's sad that the teacher had to insist rather than making sure everything had always been in cursive. Secondly, it's an easy demonstration of the mixed bag of writing types that were lazily allowed to scoot through in students' work.