There might be a few different scenarios, but outside of very specific consoles / handhelds, they’ve remained somewhat affordable tbh.

• 3DS line of handhelds, historically emulation has been good but not perfect (eg disruptive shader caching), dual-screen not being ideal on single screen setups and missing 3D effect via emulation make emulation a last resort for a number of people, myself included.
• PSVita, emulation is starting to get into its stride but nowhere near fully playable and supply of good condition OLED models is slowly dwindling.
• PS3, backcompat models have historically been pricey, especially CECHA/Bxx since they have full hw PS2 compat. Despite the usually high price point, it’s still the easiest and cheapest way to play physical PS2 games on a modern screen.

Most other “newly retro” consoles and handhelds really haven’t appreciated as much afaict, although that might be market-dependent.