Yes, MK's significance is substantially less and it's not close. Pokémon is the highest grossing media franchise of all-time, by far. Every other IP, movie, game, comic, toy, anime, cartoon, etc. you've ever enjoyed has made tremendously less money than Pokémon has- and Pokémon isn't going anywhere.
It's stronger than ever after 25 years.
Meanwhile, Mortal Kombat is roughly the fourth best-selling fighting game franchise of all time. It's not even the most popular, best-selling or influential fighting game franchise of all-time.