Good quality wipers and ceramic resistor material should do well over a million cycles of operation in the joystick, and with the 2 separate contact systems you can see there is a built in deadband in the middle to compensate, with the lower contact set simply doing a mid, up/down and full scale digital position, and with a centre tapped carbon track to make a reliable mid position voltage as well. Likely the controller provides a voltage output that is not the actual contact voltage, but a smoothed, filtered and denoised output that tracks the input faithfully but which does not jump even as the track ages.
Likely there it is a digital bus, but the data is the same. You probably have the mid position having no response till it is moved out a bit, then it has a fine position till mid range then the steps are larger till full scale near the outside. Buttons are nice with hall sensors and they probably will outlast the joystick. Having a reliable push switch is hard, and those are nice, and probably a lot cheaper than using the fully specced aerospace contact versions, which likely would not fit as they are generally deeper behind the panel. As they only do TTL level switching it is a good use, as the ones I am thinking of are rated for 115VAC400Hz/28VDC 2A use.