Much of the effect of Jaws is that it doesn't show you the shark, or the evidence the shark leaves behind, at first. The movie shows you everybody else's reaction to what they find. You absorb the unspoken message that 'something horrible is going on'. (Think about the scene where the searchers find the first girl's remains; the audience sees only her arm and hand. The actors see the whole thing; one of them gets noisily sick to his stomach; the rest are shocked) You aren't getting enough of the clues yourself to put it all together ... yet.
Looked at from 40 years later, the shark is clunky and not very realistic. But watching the movie in those first few months / years, you are so wrapped into the story that you overlook that problem; you expect to see a big shark with a mouth full of sharp teeth, and so you do. Watch Jaws now, having had time to think about the movie and digest all the reviews / commentary / analysis since then, and the clunky parts show up more strongly.
But even if you did top-notch oceanographic research and CGI'ed in a totally realistic shark as part of a remake, you still would not get the mass popular effect that the original had.