According to Osho, you repeat past mistakes because the very one trying to improve is the problem - the ego. It recycles the same hunger, first through outer achievements, then through 'inner' growth experiences, leaving the core unchanged. Real change isn't improvement but a discontinuous mutation that happens when you see the ego's game clearly; in that recognition, striving drops and the old patterning loses its grip.
You keep slipping because the same 'me' trying to get better is causing the slips; when you notice that game and stop chasing badges, real change happens by itself.