It isn't very easy to explain without graphics and plots, but here goes with just words....
Cartridge brass has a few parameters that explain the behavior. If we speak about the modulus, stress, strain, hardness state, yield, etc., then when the case is virgin it has a starting point that has a set of those parameters, and a dimensional relationship to the chamber (and dies).
Each firing cycle causes some of the properties at the body/head to change. Some of the dimensions also change depending on the pressure and deflection (strain). In most examples, the first cycle will be trivial to extract, but as the cycle count goes on, this can change.
When the dies work the body, there are more changes but that concept of yield and work hardening gets to dominate this particular discussion. The specific dimensions of a chamber or die are a "fixed" strain to the first order. (When we put this under the microscope, a chamber/bolt will actually do a significant amount of elastic stretching depending on the design.)
The pressure cycle forces the brass in the body to flex. The case head has a section stiffness right near that 200 line that goes from acting like a balloon, to having a thickness. Some of the flex during the cycle recovers, some of it doesn't, and all of it begins to work harden and change the properties.
When the dimensions of the dies, and the chamber are what I called "coordinated" earlier, that part of the case near the 200 line shrinks enough after firing-sizing-firing to prevent this clicker issue. But, when a chamber is larger than what those dies can handle, then we get to a point where the elastic to plastic parts of the problem start to tip over and resizing no longer "works".
In a balanced coordinated system, you can shoot (below a pressure level) almost indefinitely, or at least have the cycle count up to a reasonable level before the hardening of the case head and the primer pocket dimensions become a limiting factor.
In an uncoordinated system, or when the pressure always takes the brass beyond yield up in the case head with space to flow, we get to where dies might allow the brass to get back inside the chamber, but will still result in clickers on the next cycle.
As chamber reamers, dies, and brass/ammo, has improved, the problem is less common with more standardized designs. However, it takes time for designers, gunsmiths, and users, to iron out the newer ones.
A poor chambering job can set this problem up with any design, but even then when the chamber is borderline on a newer design and the cartridge is operated at higher than traditional pressures, we can see the clicker issues. YMMV
