If you can cite a case of a 60-year-old without presbyopia, then that would be the greatest medical miracle since parthenogenesis.
1. It is a myth that cursive is faster than printing. "Fluid" printing (not the block letters taught in the first grades) uses far fewer strokes. Jumping from letter to letter instead of dragging the pen between letters also uses fewer strokes and is more direct, and is thus faster.
2. Cursive is harder to read than printed letters. Some proofs of this fact: (1) the ubiquitous instruction "please print" on forms, (2) the rarity of continuous-cursive forms in typefaces used in publishing, (3) the difficulty one has in reading supposedly stellar examples of cursive penmanship, such as the US Declaration of Independence.
3. Cursive is much harder to learn than printing. Of course, for this reason it is inflicted upon schoolchildren after they have a chance to master printing, since many never succeed at it.
4. The "Palmer Method" (for example) of cursive pedagogy stifles a child's developing a personal and distinctive style of handwriting. Within reasonable limits of legibility, printing leaves more freedom for this artistic outlet.
5. The techniques of cursive handwriting are filled with self-contradictions. A "slant" is dictated as a matter of efficiency, when there is no apparent anatomical justification for this practice. Left-handers (when tolerated) are taught to mirror the slant by tipping the paper to the left instead of to the right, but the inclination of the paper has everything to do with the slant of the writing (to the right whether executed right- or left-handed) and nothing to do with which hand is manipulating the stylus.
The mindless regimentation typically used to teach cursive is antithetical to the development of studious, inquiring minds. Unlike the rote of, say, multiplication tables, the diktat of cursive handwriting is not rooted in a useful natural principle. It is most popular in cultures such as the old German and Chinese, which value rote and regimentation to a degree usually held to be extreme by, say, Americans.
In light of the above points, why does this hideous art exist at all?
6. The only justifiable reason for commonly using cursive is obsolete. People traditionally wrote in cursive from ancient times because the quill pen technology penalized you for lifting the pen from the paper. The capillary action of the ink is lost when contact is interrupted, and restoring the ink trail is not reliable, so gaps often result. This is not a factor with modern pencils, fountain pens, ball-point pens, or fiber-tip pens.
7. Therefore it is a foolish pedagogy that continues to maintain the archaic art of cursive penmanship. This subject should be eliminated from the primary school curriculum, and filed away in the universities' classics departments, where it belongs.
Only God can make random selections.