Besides being the first and last letters of the alphabet, why do we like abc and xyz so much?

In algebra, both abc and xyz are used, and occasionally pqr as well. Why those specifically? And for vectors, one of the notations is ij. Why is that? And in programming, it is a convention to use loops with ijk as the index. Why not something like cde (for count) or tuv(tally)? Why index? And in coordinates, we use xyz. Why is that? Why not abc? What about ijk, pqr, etc.? Also, why is y and z flipped in some 3D programs, and why is in some 2D programs, up is negative y rather than positive?

Finally, why do these kind of triplet letter combinations always use the Latin alphabet? Why aren’t there any conventions that use Cyrillic, Greek, Arabic, or the Latin letters with cool hats? Is it because English became the dominant language? That can’t be the only reason, as we still use some Greek symbols for some things like pi, phi, alpha(for angles as well as the particle), beta, gamma (rays), etc. The Greeks figured out things like coordinates, algebra, etc., so why Latin letters? Is it because of the Romans?