Without knowing much of how it actually plays out in practice, my first guess would be that politicians with the power to create government in opposition regimes would choose *not* to– because that would require handing over some of their current power to the opposing party, and any benefits gained at a later date would probably go not to them but to their successors. And politicians in a declining majority would have a hard time passing such major structural changes, as, presumably, if they can recognize they’re heading out so can the rising majority, who would attempt to block some structures knowing that they’ll soon be on top.