Demand has dropped across all market segments but among some, prices seem steady.
For city dwellers, vintage uprights / middle weight bikes with 3 speeds are once again selling. You couldn't give them away just five years ago. More remarkable its becoming fashionable cool with the gals. No need for mint or excellent cosmetic condition. Long as they're in good mechanical, clean and can still present character. $190-$290 range. Mixte's outsell the men's frame though both versions sell. Often fetch more money than skinny tired race bikes.
Another quirky used bike segment are older 26" MTB hardtail conversions to upright stems, drop bars, mudguards. Contrary, older road bikes converted to flat bars just don't seem to appeal buyers.
Other:
Vintage BMX still way strong.
Sleeper market.... older hybrids with ERTO 584 (aka 27.5 or 650b). Especially the forgotten Schwimn Suburban 1980's, three speeds. $200-$250 all day long.
Ps: Moved 400+ used in a 6 week ~weekend stretch during covid holiday. Lol