Isn't it the mathematics that is lagging? Amplituhedron? Higher dimensional models?
Fun fact: I got to read the thesis of one my uncles who was a young professor back in the 90's. Right when they were discovering bosons. They were already modelling them as tensors back then. And probably multilinear transformations.
Now that I am grown I can understand a little more, I was about 10 years old back then. I had no idea he was studying and teaching the state of the art. xD
Tensors are like 200 years old in mathematics. Gauss talked about Tensors.
Tensors are pretty old in physics; they are a central concept in Einstein's General Relativity.
You can find tensors even in some niche stuff in macroeconomics.