To survive in boxing sport then they need to change their styles. Boxers like Rigondeaux, Lara, and BJS are having no job in boxing and their boxing careers are jeopardy. A fewer and fewer boxing fans are interested in watching them. I do know that it's not easy to change their style but if you don't want to be forgotten then you need to do it.
Rigo did against Ceja, and Floyd did against McGregor. So yeah, they can and fairly easily. Also, watch Saunders vs Hall, he walked him down and beat his ass from start to finish.
What you said above was just a temporary change not a permanent one. Whey they face tough opponents then they will employ the same boring style again. I guess
It quite common among elite fighters. When they face other elite fighters, there's a higher probability that they're going to get knocked out if they fight recklessly, so they don't risk it. But if they think their opponent poses no threat, they put on a show for the fans, tricking them occasionally into believing they're something they're not. Golovkin does this all the time, goes in there and blasts out his bummier opponents, and when in with a big puncher or an elite fighter he plays it safe. The ironic thing with Kovalev is, most so-called slick fighters would have several KO losses on their record if they fought the way that Kovalev used to fight, all the time. His gas tank used to be fuller and his chin more sturdy, but he got old, so now he's gone the slick defensive route too. With him it's a matter of necessity, well guess what, with most of these slick fighters it is too. Because most of them don't have much power or a good chin to begin with.
Depends on the boxer. The best out-boxers are entertaining to watch even when not fully engaging. Bit different to a Johnny Nelson.
They can, but it comes at a risk. Joe Frazier changed the way Marvis fought and forced him to be a more aggressive fighter, since he thought the more passive style that Benton taught him would bore the audience and make him an undesirable opponent.
Usually with great "defensive first" fighters, be it shell or backfoot, it happens when they age. They slow down in footspeed, head movement, punch volume, and overall stamina... all leads to a recipe that will feature them getting hit more and being in range more at least. The greats will fire back and find a way. See: Whitaker vs. Hurtado, Hopkins vs. Pascal, Mayweather vs. Maidana I. Using a slightly lesser example, Calderon vs. Segura I and an even lesser example being Lara vs. Hurd, though both of those were in losing efforts.
Crawford is the king at changing styles which is why i pick him to beat spence. Canelo has become a pressure fighter since moving up to 160 also.