Half-Life is also a pretty bad example because the OpenGL renderer resizes certain textures and with that it makes the game blurrier by default even when you turn filtering off. Half-Life however is kind of a mixed bag: nowadays I turn texture filtering off when I play HL1 because I prefer the overall sharper looking textures but basically everything transparent looks worse because of those visible individual pixels. I would never turn on texture filtering for a 2.5D sprite-based game but it's pretty obvious that those titles were never designed with the feature in mind (and personally I view things like Blood's never finished 3Dfx implementation as desperate attempts to 'keep up with the times' instead of them being artistic decisions).

Developers also found certain solutions to ease up on the blurriness pretty quickly, features like detail textures appeared around 2000 to make stuff seem more detailed from up close. In those low resolutions 3D games easily looked better with texture filtering, it did wonders to smooth out the image (also: stuff like anti aliasing and anisotropic filtering wasn't really a thing for a while so really apart from the filtered textures the games still looked 'messy enough').

Exactly, thanks for pointing these things out.

Doom hi res textures