Cursive writing was invented for the fountain pen.
When fountain pens would blot or smear was when you lift them off the page. As a result writing at what we now consider "normal" Speed was only possible if you minimized the number of times you lifted the pen.
Cursive was a writing style developed in which all the letters of a given word were conjoined in a free flowing motion.
Worked well for the fountain pen, but was also unforgiving and could become virtually unreadable unless written nearly perfectly.
As a result there had to be an emphasis on "penmanship" or precise writing.
My parents went to elementary school in the 1960s, middle school right around the early 1970s and high school in the mid and late 1970s
By the time either of them got to high school, the "stick" type cheap Bic pen was ubiquitous, and was essentially the "standard" in most high schools.
You ask most people who graduated the same year my father did (1977) or the same year my mother did (1979) and most had probably SEEN an actual fountain pen but had never attempted to actually use one. By the time I gt to high school in the 1990s none of the teachers had ever even SEEN an actual working fountain pen and the modern rollerball had become the standard.
Bureaucratic inertia, combined with political pressure however meant that, although fountain pens were anywhere from 40 to 60 years obsolete by the time my parents came along. and really hadn't been in high schools in 30 years, they were STILL required to use Cursive writing. And they DID have to waste time on "penmanship" It still affected grades.
As soon as my father was out of high school, he stopped using it for anything but his signature. Largely because he was tired of getting hectored constantly over his "penmanship" Even had one asshole teacher tell him, " Your handwriting could stop a moose cold at 40 paces!" Mom fared a little better and continued to write in cursive until she disappeared.
So, cursive is an obsolete style of writing, designed for an obsolete technology, that mercifully modern students don't have to waste any time with, unless they are interested in stuff handwritten by their grandparents or great grandparents.