20-Year Prospect
There's no indication that people will stop wanting to watch entertaining acts of brutality in the future. In fact, folks are spending more time and money on paid TV programming and events, so don't worry about the field of professional fighting going anywhere. If you can kick world-class butt, there will be plenty of people who want to watch and idolize you. The only teensy sacrifice you have to make is, you know, brain damage.
Publicity is the name of the game. As social media expands to control the minds of the masses, Internet-related hype will be an important tool to help you win those hearts and minds. Just don't take publicity stunts too far. If someone asks you to be in a human vs. robot exhibition in a decade or so, maybe sleep on it. Of course, we're holding out hope that the robot takeover won't be for another forty years at least.
The rules and regulations of pro boxing will likely not change much over time because it is a well-established sport with respected traditions. However, if you are going to make this your career, be mindful that it will become harder to stay healthy and in fighting form as you age. Unless, of course, your end game is to become a biomechanical punch-bot once the technology is available.
It might seem like we're a little obsessed with this cyborg thing, but because of the limitations of the human body, there are not a whole lot of professional boxers over forty. The oldest boxer ever to win a world title was Bernard Hopkins, at age forty-nine (source). That means if you're just getting ready to break into this field, be ready to exit in about twenty years. The best thing to do is to train hard and retire early with as many of your teeth as possible.