If a person who liked killing people stopped killing as many people every year and only killed as many people over a longer period of time, that can count for criminals/psychopaths as "better and better".

If a government decided to take less bribes and still continued the system of brutal oppression upon its people, the government can still claim that it's getting "better and better".

If a whole system treats its people like frogs being boiled in warm water and decided to slow down its process, the powers that be which run this system can also claim to be getting "better and better". Heck sometimes they even claim to be moral people because they slowed down the boiling process.

For the rest of us with some common sense, the "better and better" thing can be understood in the same light as every single outdated philosophy/customs/cultural outlook/systems that have been discarded into the rubbish pile throughout mankind's periods. This is just another dogma that is fed to us by the wicked to lie and cheat others.