320x240 aka modeX was _never_ a common resolution in DOS. In fact it was almost not a thing at all. I dont know of any games pre 1996 Quake that would support it at all, and only 1997 Lost Wikings 2 used it by default. Quake of course ran 320x200 out of the box.
320x240 became somewhat popular with advent of snail 3d Decelerators in early directX games.
640x480x256 indeed started being popular in 1994, another example Transport Tycoon.
60fps was very much a golden standard you experienced in the Arcades since the eighties, and something everyone wanted even though most people didnt know the name for it yet 😀. Not fluid, slower, choppy, acceptable was how people talked about framerate without mentioning the word "framerate" or actual numbers back then. "Good" Arcade conversions did 30 fps, 3dfx Voodoo1 aimed at delivering 30fps, some games even shipped with 30 fps vsync (1996 Tomb Raider), 30 fps was good enough for home gamers. Console gamers could taste very limited 240p@60 selection up to 1997 https://www.sega-16.com/forum/showthread.php? … ration-Consoles with most 60 fps games showing up in 1998. On PC front in 1998 Pentium 2 became popular (still >=$600), Celerons 300A came out ($150) and Voodoo 2 dropped ($350), this is where people finally started playing at 60fps either in software (Quake 1 320x200 P2/Celeron 300MHz) of accelerated (Quake 1/2 800x600 Voodoo2, 1024x768 SLI V2). AMD fans had to wait another year for a CPU capable of reaching 60fps 😀.