Or people just don't need to write as much, especially not in cursive since it only adds legibility problems.

In America at least, The headline is just not true. Computers, phones, and tablets are killing cursive, full stop. Ballpoints killed fountain pens as a general purpose writing instrument, it's true, but that was literally fifty years ago in public schools in the US. Cursive however, kept on truckin'. Even in the 80s and 90s, we learned with pencils, and did exams and in-class writing with ballpoints and maybe a fancy-pants rollerball. By college, I was using fountain pens because I'm a dork who never found the obsolete text-generation tool I didn't find interesting, but the rest of my classmates were contentedly doing their papers with their Bics. Even the article from the 60s, cited in the story, was written by a "researcher" who worked for a private company selling handwriting lessons.

It's only as laptops became so common as to be practical and permitted in classrooms that the mindset changed. Keyboarding had a brief heyday as a skill for everyone, but now even that is fading as students are most comfortable with touch-screens of various sizes. My nine year old doesn't touch type, but merely being familiar with the location and uses of the keys on a fullsize keyboard has set her apart among her peers. Her kids will probably wonder how she managed to get along without full-time transcription. Funnily enough, her manuscript is god-awful, with so many unconnected loops and ascenders that a letter could sometimes be any of three or four, but the little bit of cursive they have learned, encouraged by her dear-old chicken-scratch dad, is more legible. I don't want to imply that's the norm, though. Most people's cursive is much harder to decipher without context than their printing. Then, as we write by hand less overall, the need to optimize for speed and comfort becomes less pronounced. Easy, legible letter forms that are just slower to make are fine.

So that being said, are fountain pens in good working order and with ink in them nicer for cursive? Hell yes, of course they are! They were generally built to last, so more thoughtfully designed for a writer, the technology allows for less pressure (though the required pressure for writing on a single piece of paper can sometimes be overstated by us enthusiasts) and more "personality." That said, 95% of people didn't care about any of that enough to want to stick with fountain pens even when ballpoints were less mature than they are now. That was doubly true because we as colelctors have some serious survivors' bias around the brands that have lasted and particularly the vintage pens that hung around. Anything cheaper than an Esterbrook J barely matters to a collector, but that the leaky plastic bananas of many a bulk-lot Ebay listing made up the vast majority of fountain pens most people were dealing with. They are literal garbage now, but they weren't far off back then.

Cursive or print, most people just want a convenient stick to put ink onto paper.

Yeah ballpoint pens are probably killing voicemail, too.

Or, you know, the fact that typing is generally faster and more legible.

Or people like me have Autism and ADHD, this lacking the fine motor control for handwriting.

My "handwriting" ended up with me being the only kid in school that was permitted to hand in all my written work by typing it up on computer and printing it out. In 1990.