Part of me wants to say "Video Games are an escape and should set out to be as far out and awesome as possible."Need a Dispenser said:snip
But the other part of me wants to say "Realism can still be considered an important aspect of the experience, depending on the genre."
It all boils down to creativity in general. The more grounded in reality something is, the more believable and accessible it will be to your audience. It's why some of the greatest fantasy movies or novels start small and become more fantastical as it progresses. If things start out too whimsical, you risk alienating a large chunk of the audience.
The opposite of this would be the Uncanny Valley effect where an attempt at being too realistic creates a grey area.
Gaming didn't start out with its roots in reality. Some of the first games released actively involved your imagination to make things work. You had the elements there for you on the screen, but they wouldn't fully represent what they were. Having this reverse accessibility approach allowed games to be as crazy and imaginative as possible, simply because gamers viewed this as "par for the course".
With advances in technology, developers realized they had the potential to make games more believable. That's exactly what they set out to do. Now games rarely need you to think outside the box to believe what's in front of you. There are still elements of fantasy, sure, but it's not nearly as prevalent as it used to be. Thus, games became more accessible.