As someone who hasn't seen it in the flesh yet, and doesn't "get" modern art unless someone explicitly spells it out for me, could you elaborate more on why it's so spectacular?
For example, Blue Monochrome [1] seems to my uneducated eye to be just a layer of pure blue that every wall painter recreates every time they paint a wall blue. Why is the Blue Monochrome piece more than just a wall painted blue?
Klein blue is outside the color gamut that can be represented on normal monitors, so it's physically impossible to get the full impact of it through a picture. It just looks .. deeper.
There are a few flowers that have this property; fuscias, and others with strong UV fluorescence.
Consider the time period and the historical context. It's modern times, Cold War is occurring, and WW1 and WW2 left scars across Western Europe and caused major changes in the art world, including being a boon to abstraction and fragmenting styles into many eclectic directions.
Chemistry has DRASTICALLY altered painting from the Renaissance to the World War era. New pigments have been constantly highlighted and displayed in artwork. Finally, an insanely blue blue has been invented, bluer than any other blue paint in the past.
The artist highlighted above attempts to showcase the new technology in its purest form. Though, despite this strive for purity of blue, the application is inherently uneven. If you look into the painted canvas up close, you will see imperfections and patterns in "just a wall". It's also a statement, it may cause reactions and cause viewers to question the boundary between art and not-art.
It's not my cup of tea compared to masterworks of Van Gogh or Homer or any of the legendary painters, but art goes through many phases and is used to express many different ideas. What I do think is bonkers is that modern artists (who are well-connected) may be paid millions of dollars for these works, which to me don't showcase skill and talent, but which reward creative ideation and concepts.
> Finally, an insanely blue blue has been invented, bluer than any other blue paint in the past. The artist highlighted above attempts to showcase the new technology in its purest form.
I was thinking something along these lines. Based on the first Wiki article, Klein was involved in developing this pigment. If so, the work stands on the merits of that achievement alone. He was, for that moment, literally the only person in the world that could have created that painting.
There’s a really great short story by Alistair Reynolds about an artist that’s obsessed with a certain Zima blue (name of the story) which is essentially an extended meditation on the above, I think you might like it. :)
There's some great answers to your question below, but I'll add mine anyway. Because of the way our eyes see blue (as highlighted in the OP), and especially Yves Klein blue, it has some slightly magical properties in art. The flat blue canvases are absolutely uninspiring at first glance, but stand in front of it for 30 seconds and it starts to recede - it becomes hard to tell how far away the canvas actually is. You're unable to make out texture on the surface because the brain is struggling to actually work it out. It's most striking on the sculptures though, they almost entirely lose their depth and become a flat thing that changes shape as you moved around it. Imagine a 3d rendering of a gallery scene where there's one model that is untextured and unlit - it's like a brilliant blue silhouette.
I took my then 5 year old daughter to the Tate for the exhibition and it had the same effect on her, while almost everything else on show had no effect at all. The only other thing she loved was Bridget Riley, and I think Yves Klein's blue work is somewhere in the same realm - the art is in defining something that makes the viewer's brain do some of the work, that is going to be experienced slightly differently by everyone who sees it.
I like to wander around art museums, and on one visit, I shared a gallery with what seemed like a private tour group.
One woman was conducting the tour for three people, when they stopped at one of these all-white paintings.
She was describing the potential meaning behind the work, and noted that sometimes the artist expresses textures, or covers some background work.
It's hard to describe, but I felt this sort of absurdist joy when I watched all four of them lean in very closely for half a minute, only to discover absolutely nothing unique about the work in its texture or color.
Maybe sometimes art isn't made for the observer, but the observer's observer.
As mentioned above, it just looks different in person, that picture does not do it justice by any means. It's kinda like when you see a 3D render with inaccurate physics, but this one is in the real world - it feels out of place. Or like catching a really pink sunset: you can look at it for as long as you want and the color never ceases to impress you.
For example, Blue Monochrome [1] seems to my uneducated eye to be just a layer of pure blue that every wall painter recreates every time they paint a wall blue. Why is the Blue Monochrome piece more than just a wall painted blue?
[1] https://www.moma.org/collection/works/80103