George F. Paul’s letter in the November 1989 issue says it was a fairly long wait until laterally cut disc recordings became either cheaper or better than vertically cut cylinders, which would tend to make one wonder how the disc won out.
In point of fact, the disc recording was both cheaper and better. Disc records were cheaper to make because they could be molded, while cylinders had to be individually cut: The “flashing” where the two mold halves meet occurs on the unplayed edge of a disc, but twice per groove in a cylinder. (Eventually, the cylinder people solved that, but it took a while.) That being the case, I imagine that either the price of disc recordings soon dropped below that of cylinders or an increased profit margin on discs encouraged dealers to push them.
Discs are also a far more compact storage medium. Discs stack flat, with little wasted space; when you store cylinders, you store a quantity of air inside each one’s center tunnel.
Incidentally, vertically cut “hill and dale” discs were also issued (by Pathé, as I recall, and probably by others). Today’s stereo phonograph cartridges, which respond to both vertical and lateral groove displacements, can be used to play these discs and cylinders, if the leads on one channel of the cartridge are reversed; styli for old groove shapes are also available for some current cartridges.