The main reason why Jurassic Park looks so great was because of how little CGI it used. It was almost all practical effects.

But Terminator 2 dramatically altered the public perception of CGI. Before T2, computer graphics was perceived as primitive and clunky. The first film to use massive amounts of CGI, The Last Starfighter, had a middling reception and people were not very impressed (they should have been, though, considering the technical level).

Then The Abyss featured a CGI special effect which started to change perceptions - the water creature was something tradtional SFX just couldn't do. And viewers were captivated by it.

T2 took the effect from The Abyss and took it to the next level. Now, going from the transparent rippling water substance to reflective metal allowed a lot of effects to be practical. And indeed, T2 had a lot of practical effects. But it's the CGI which really captured the public imagination, and the filmmakers were fine with the public believing the myth that it was all CGI.

So, by the time we get to Jurassic Park, CGI was seen as the hot cutting edge technology. Directors like Spielberg and Lucas wanted audiences to think that they were getting the latest and greatest SFX, and that meant CGI (never mind that they were also pushing the bleeding edge with practical effects also).

Remember, this is the era when Sega was selling their Genesis console as having "Blast Processing". What the heck is "Blast Processing". No one knows. But it sure as heck is something that Genesis has but Nintendo doesn't.

Of course, it's not all technical prowess. I would guess that the most remembered special effect in Jurassic Park is a practical effect which is memorable because of the artistic emotional effect rather than technical impressiveness. I don't think anyone was impressed with a couple cheap plastic cups on a technical level.

So many productions on TV and movies rely on CGI, even when ppl don't really notice that the background they're seeing in historical movies is not real. It's amazing and seamless. For example, Midway could not have been made without it yet, it's able to evoke a visceral response. Green screen & optical effects are so accepted, it's impossible to tell reality.