Notwithstanding NihilCredo's point, the lack of gladiatorial combat today is most likely due to a genuine change in taste, probably related to secular decline in social violence and availability of increasingly varied entertainment (movie theaters, TV, video games etc.).

For gladiatorial games specifically, their decline was caused by Christian objections. Sorry, you don't get to redefine historical facts just because they don't fit your narrative.

gathering scores of cats and burning them in a fire.

Wait, that sounds like fun.