Btw, my father back in the 80's(?) had a high end audio cassette player that could let you adjust playback speed and set pitch so you could listen to lectures at faster rates while preserving pitch.
Yeah the technology is old by remember all the sources were analog. But for those you pretty much have an "infinite" sample you're reading and changing as you drag it across some sort of tape head (or record needle). (Ok not infinite but you know what I mean).
But digital recordings only have so many samples per second when if you expand a give sample it now has to go further. This would definitely lower quality.