Why an electron and a positron should have the same lifespan? According to Particle Data Group:

source: data
Particles and their antiparticles (i.e. antimatter) have the same lifespan.
The electron/positron for example have a minimum of 6.6E28 yr. This was experimentally verified for the electron here in this 2015 paper:
paper (see also here in this story cover article IOP)
Nevertheless, there is no any experimental verification of why stable antiparticles like the positron should have the same lifespan with their normal particles counterparts (e.g. electron)?
Seems to me that this is more like a theoretical ansatz.
Is there any experimental verification ever for the above?
This might be crucial information. Maybe besides charge and chirality there is something else going on concerning the interaction of stable antiparticles with vacuum space that could explain why matter is dominant in our Universe and not annihilated with the production of equal amount of matter and antimatter during the Big Bang?
 A: In the table, all the particles except the electron and positron (and the proton-antiproton) are particles which decay. The decay rates allow the calculation of the lifetime of these particles and that is what is shown on the last column. Note that the electron and positron have a reference (1), which you have not copied for us, and the link you give is not from the publication itself, just for the image in wikipedia.
(1)

Borexino is a liquid scintillation detector located deep underground at the Laboratori Nazionali del Gran Sasso (LNGS, Italy). Thanks to the unmatched radio purity of the scintillator, and to the well understood detector response at low energy, a new limit on the stability of the electron for decay into a neutrino and a single monoenergetic photon was obtained. This new bound, $τ>6.6*10^{28}$ yr at 90%  C.L., is 2 orders of magnitude better than the previous limit. rest of the numbers are lifetimes derived from experiments measuring the decays of the particles, but for the electron and positron this must be the  lower lifetime limit from experiment .

The limits for the particles that decay shown  in the table are due to experimental and calculational errors, not to the lifetime, if there is one; the number says that the electron is stable within experimental  errors.
Within the standard model, the lifetimes of antiparticles are the same as for particles, and this has been checked by experiment.
But even if one could have a corresponding experiment for positrons the experimental errors would say nothing about the axiomatic symmetry on lifetimes between electron and positron. The experiments for the positron would be different and much more difficult to perform so the experimental errors would be different, but this would be irrelevant for testing the standard model axiomatic assumptions.
The same is true for what is given on the right for the proton antiproton, that might decay as some models predict. It is the proton whose lifetime  can be checked very accurately. Antiprotons carry the problems of production and easy annihilation in any experimental setup.
