Because it's not profitable. Modern versions of cathedrals would have corporate sponsors.

https://en.wikipedia.org/wiki/Wat_Rong_Khun

Opened in 1997. The murals inside are full of contemporary references like Goku and Master Chief

This but unironically. What was once a marvel is now mundane.

Modern skyscrapers are built with base isolation and mass dampening to make them resistant to earthquakes. Have you seen recent cargo ships? Warehouses? They are great and awful in every sense of both words.

Brazilian Giant Rubber Duck

Reminder that big government science projects, like space programs and supercolliders, count as wonders.

The LHC is 27km in circumference. Still not as big as the Great Wall of China.

ETA: The Burj Khalifa is certainly a wonder of engineering, if it's not regarded as a wonder, itself. But it's the first occupiable tower to exceed Barad-dûr. (Tolkien fans have since adjusted the Sauron's tower to be even taller.)

Because humans stopped reading in a coherent direction.

I mean, the first one definitely makes me go "Hmm, I wonder why anyone would build that?"

We have stopped building wonders because the modern contractor industry is built deliberately to waste as much money as possible by letting it all go towards middle managers and people at the top.

The government is complicit in financing and upholding this system and has stopped employing people directly to actually do productive building work.

This is hamstringing us, because it means that we are literally uncapble of building great things. All things we try to build will be infinitely delayed and sever times the original budget. Because then, middle managers will be able to suck more money out of the broken system.

Bridges in the US now cost more than entire rail networks back in the day or what the sagrada familia cost over 100 years.

we didn't, Australia has architectural marvels like the Big Prawn, the Big Banana etc

For a sec I thought the bottom image was DS3 Anor Londo and was wondering what game the upper image was from

I present to you, China:

When you have slave labor and authoritarian control, building aesthetic wonders is easy.

I think because finding a quarry with that much quality stone is impossible these days unless you dig very, very deep and ship it likely halfway across the world. Possible of course but prohibitively expensive, not to mention how much fossil fuel will be burned to achieve it.