I wonder why Shadowrun didn't keep up
Because Shadowrun's setting is a split from the idea of cyberpunk in the mid-80s. Holographic sights weren't even a concept, but SmartGuns were. So with Smartguns, who needs a holographic sight?
I presume that a Holographic Weapon sight will give a +1 accurancy who cannot be add to a Smartlink or laser sight and I pretty sure that no wireless could be apply
the problem with this idea is that a Holographic Weapon sight don't come with the normal malus of a laser sight, the easy to spot problem when using one
so I think that this piece of equipment was omitted to keep some kind of balance to the game but have no way to knowing, so it just conjectures
Red dot sights were introduced in Gun H(e)aven 1, page 22. Bear in mind this was for 4th edition, so the rules from that book don't really translate well into 5th edition. But here's what the book said:
VINTAGE ELECTRONIC SIGHTING AID
Mount: Top Avail: 3 Cost: 200
The red dot sight is a precursor to the modern smartlink system. It was frequently added to military rifles at the beginning of the century, but was supplanted by modern aiming aids as technology progressed. The sight provides a +1 dice pool modifier.
If you were to try to implement this in 5th edition, it would probably confer a +1 to Accuracy. Also, it's worth noting that the beams from laser sights aren't visible unless the air is misty. Generally, the only part of a laser sight you'll see is the dot. Which is almost imperceptible if you're on the receiving end of one. Not to mention the awesomeness of infrared laser sights, which are totally invisible to normal sight.