Fun fact: in CS 1.6 it could actually be reverted to the old-style WON UI by with `setinfo "_vgui_menus" "0"` in config.cfg or in the console, or buried in the menus as "Options > Multiplayer > Advanced > Buy menu type > VGUI Menus".
Yeah the text-based menus were what Half-Life launched with in 1998. Counter-Strike used these same text-based menus in 1999 and it wasn't until 2000 that the engine was updated to include VGUI. I guess Counter-Strike left the old ones in place for those that preferred them.
Fun fact: in CS 1.6 it could actually be reverted to the old-style WON UI by with `setinfo "_vgui_menus" "0"` in config.cfg or in the console, or buried in the menus as "Options > Multiplayer > Advanced > Buy menu type > VGUI Menus".