When some fundamental new theory is published, derived work will be done "instantly", example from quantum mechanics:
1926 Schrödinger equation
1927 The first application of quantum mechanics to the diatomic hydrogen molecule
1928 The concept of the Bloch state
1928 Relativistic quantum mechanics
1940s Quantum electrodynmics.
But wave guide theory is only published in 1897 On the Passage of Electric Waves through Tubes
The above QM theories are much more "harder" than the theory of wave guide, then why is it published after such a long timer after Maxwell's equations were published?