MacOS was behind the times vs. Windows. Still sticking with cooperative multitasking until 2000. Crazy!
iMac was the start of something different, but Apple had a decade of second-class product to atone for, first.
To be fair, sticking with it until 2000 wasn't Apple's intention; they'd expected to bring the new "Copland" Mac OS to market by the end of 1996.
I don't know how well the iMac may have sold at the OP's Best Buy, but my recollection -- and a web search just now seems to back this up -- is that the iMac sold very well pretty quickly after its 1998 introduction. For instance, a NYT article from January 1999 which begins:
"Apple Computer Inc.'s popular iMac desktop computer was the No. 1 selling machine through retail and mail-order channels in the 1998 holiday season, according to the research company PC Data.
"In overall sales, the iMac fell from the top spot in November to No. 3 in December. It is still the top-selling computer since its mid-August introduction and led overall sales in the fourth quarter, PC Data, of Reston, Va., reported."
https://www.nytimes.com/1999/01/22/business/apple-s-imac-led...