A problem I talk about a lot in terms of minidisc is that Sony made weird or poor choices in terms of marketing and selling the format. Sometimes this is as simple as "refusing to tell people minidisc recorders can record" but a lot of the time it's as big as "Sony sells an incomplete ecosystem outside of Japan".
(Not Just Bikes voice) I'll talk more about some of those things later on.
There was one moment Sony did almost everything right and sold all the parts of the format globally. The MDLP Era.
TL;DR - The MDLP Era was a moment where prices came down and you could buy nearly the full ecosystem in the US.
EDIT NOTE: See my comment, I found out some more pricing information that alters some of the proposals I've made here slightly, but not too much. The prices "declined a bit" not halved, because Sony left a model from very early 1999 on sale in early 2001, which is something that can be tough to account for when you're writing this kind of interpretive narrative. My apologies for this.