Why is The Sims 4 (released version) not like the Official Gameplay trailer 2013

Why is the 'The Sims 4' game not exactly like the 

Official Gameplay Trailer that was released in 2013-

There are very obvious difference/s from the sims creation themselves-

Please tell me why is this the case-

because when the Game was released after this- - the sims creation itself looks and still looks grainy and 

the quality is not the same as the Trailer that was released-

I feel as though the trailer pushed as a marketing ploy to entice me to go as far as buying the Collector's Edition-]but then when I compare the Video

and then look at my game, I notice the graphic comparison/s and the UI also changed almost immediately...

Please get back to me with a response