They were established stars before cancel culture, but I doubt they'd agree with your assessment. Getting fired has an immediate effect on the speaker but it creates a cascade as others fear crossing somebody's line. This aint new, the right has been canceling people for decades. Trump even did it to the kneelers and his damn job is supposed to protect free speech.
"They" probably wouldn't, IDGAF, they can get a normie job like the rest of us.
I also know this isn't new, in fact I'd say it's always been here and it isn't going anywhere. It's just living in society. It's theorized that if King Arthur were real he was stricken from history by the church for some transgression, possibly consorting with a pagan medium? Both Theodora and Catherine the Great are surrounded by salacious rumors many speculate are completely false and just there to undermine their legacy. I mentioned earlier in this thread that Tom Sawyer was banned from libraries in the past because people thought the protagonist was immoral. Reagan got his political chops by narcing out fellow actors who'd said things that could be construed as Marxist. The Satanic Panic that went after heavy metal and tabletop RPGs was in full swing before Tipper Gore went on a crusade against bad language in music. Michael Richards tanked his career long before Trump bagged on the kneelers. Sometimes the sniping is successful, sometimes it isn't but it isn't going anywhere.
As Lexicus pointed out sometimes it's a useful tool like in the Civil Rights Movement. Boycotting also helped end Apartheid in South Africa when people joined a BDS style movement against South Africa. Speaking of BDS there's legitimate threats to free speech in laws and contracts that require people to abandon the BDS movement. Unlike the opinions of a bunch of Twitter users that's an actual first amendment violation.
What if the reaction shackles free speech? If every person in this country had the power to fire anyone who says anything they find offensive, what would happen? I have shackled my reaction because cancel culture inhibits free speech. Besides, the issue is plagued by the selective outrage of partisan politics. Roseanne Barr would have survived her joke if she was an Obama supporter.
If Roseanne had made a racist and bigoted slur about an African American on Twitter I doubt "but I'm an Obama supporter" would have helped her much. The only difference is fewer right wingers would be jumping to her defense.
Two things will protect anyone from "cancel culture." Talent, ie Mel Gibson's comeback after his wacko anti-Semitic rant. Roseanne got booted from a TV show but don't feel bad, she could still sell out clubs all over if she decided to tour. I've seen lefties try to pretend Ted Nugent isn't any good but I've seen the guy in concert 3 times, he can rock and he's doing fine. The other protection, and this is the one that matters, truth and/or merit behind your offensive speech. They tried their damndest to "cancel" Muhammad Ali, didn't work. He was right about the war. They tried to smear (and still try) MLKjr with rumors of affairs and whatnot, doesn't work, he was right about race and inequality. The NFL tried to cancel Kaepernick but he got a Nike deal anyway and plenty of people have been pushing back against his blackballing. If a team ever does sign him they'll triple their merchandise sales overnight. Canceling didn't work, he's right about police violence.
If you don't have either truth and merit or talent on your side it might be a good idea to be careful how you use your freedoms.