Why was there no PS1 and N64 port of Half-life?

[wildweasel]

Bear in mind the PS1 struggles to run games that need a lot of sprites, because the system doesn't have much RAM (for graphics or otherwise!) - it's a lot cheaper on the RAM to handle polygonal models than a sheet of animated sprites. A more apt comparison, PS1-wise, would probably be the Quake II port, or for something that plays to the system's strengths, Medal of Honor: Underground.

[Viscra Maelstrom]

i only have a demo of the Q2 port, but i recall it running really well from what i played. Doom in comparison plays alright... in the levels that were ported from the Jaguar version. the original levels and especially later Doom 2 levels ran like ass, and there's even the issue that the game can outright crash due to lack of memory (i think it was in Suburbs, due to the amount of actors you can wake up simultaneously). similarily, the Final Doom port is outright worse, as the levels are much bigger in scale and doesn't run very well at all, not to mention having a bit less than half the maps of the first port.

[Cacodemon345]

All of the issues are well due to the limitations in the first 3D generation era consoles.