In the early 1930s, scientists were fairly confident (meaning there was consensus) they understood subatomic physics.
The vague term ‘fairly confident’ needed definition in today’s modern language.
They had a working understanding of nuclear physics, and this has stood up. The further forays deeper into the subatomic realm, or realms, has been ongoing through the 60's, 70's and later. I remember the excitement over the J/psi particle, back in the day. It too, was a "resonance", i.e. a "bump" in a curve of reaction cross section versus energy.
I note the Upsilon Meson was discovered about the same time. Here's a very quaint figure from the paper announcing it:
Now we have detectors the size of battle ships with INSANE computing power ( based on 1930's concepts of solid state physics, however finally honed, ) and we get tetraquarks.
OK, great.