Not quite, and an interesting story that fits these engineering maxims better than you might think.

Huh? The SotA for dial-up modems in the 1990s was indeed 56 kbps, achieved with various encoding and compression hacks in both domains including trellis coding.

Weirdly enough, you can apparently still buy them from US Robotics: https://www.usr.com/products/56k-dial-up-modems/