It's kind of sickening how much it costs to make a game these days... Mind you I'm sure lots of that are overblown upper management salaries and what not.
You also have to keep in mind how much has changed, back then we didn't have all these shiny graphics, effects, voice-overs, sound effects and variables.
Mario 64 had some great stuff, but it was basic grass, sand, wood, castle and a few other colors here and there. Compare the lighting and detail to games like COD and God of War III now.
Back then it was easy to just pull off a few graphics and detail, Ocarina of Time just got some day and night cycle and slapped on skeletons and ghosts for the night. GTA III added a working timer and it wasn't until GTA IV where more detail was added.
Back then the open world was just there, RDR and GTA V added a crapton of detail, simple things like vehicle damage, killing birds with rotors, hunting animals, wind direction and many others are in GTA V. That is why it is hard to make games now, gamers get a lot more with $60 than they have ever done before.