Why don't we have invisibility cloaks?

Why don't we still have invisibility cloaks... It's been nearly twenty years since the first Harry Potter movie.
Interesting Engineering

Remember all those embarrassing times when you sunk low in your seat and wished for no one to see you? Or the tangent spurred on from that moment when you wondered when you would be gifted an invisibility cloak, just like the one Harry Potter did in the first movie? Oh, is it not just me, then? Aha! Well, those cloaks do not exist. Or do they?

You see, when Harry first put the cloak on and his body disappeared, it was the Visual Effects Department who applied a green screen effect over this one-of-a-kind cloak made for the movie using a unique velvet fabric adorned with Celtic designs and ancient runes. 

But what about us peasants living in reality? 

Do we get one too? 

Are we wizards now? 

Or is it just not magic? 

Oh, is it science? 

Isn't that awesome?

The purpose of an invisibility cloak is to conceal things under it, and the easiest way to hide things is to bend light. No, we’re not Lightbenders yet, so we need the assistance of metamaterials to create the illusion. Metamaterials are substances that are man-made: they do not exist in nature. Some of these give the impression of invisibility when a cloak is made using them and puts their light-bending properties to use.

And if that seems complicated, then you would be pleased to know of Quantum Stealth, a new creation of a Canadian-based company, a thin veil that bends light. It gives an efficient result in all wavelengths of light and bends the light hitting the back towards the observer from both sides, thereby creating a blind spot in the middle. However, objects need to be a certain threshold distance from the material to disappear; they become visible once again should they get too far. Current prototypes give a blurred image to the background, but it is just a matter of time before we marvel at future models that display a sharp image.

Perhaps it would take us just a couple more years to get our hands on an invisibility cloak. Now all I have to do is stay clear of embarrassing situations until then.