My band had to join AFM to record for Capitol records back in the 90s. Part of the deal, house rules, all musicians had to be AFM to be on the label. So we went to the office of our local to sign up and it was one unforgettably hilarious experience. The president of the local, Byron, wore shades the whole time. He sat behind his desk chain smoking, trying to impress us with stories about storming weddings that had hired non-union bands, beating up a non-union DJ at a pipe fitters convention, shutting down jam sessions. Enter his secretary, who also wore shades, had a super tight perm, was about 5’8” and couldn’t have weighed more than 85lbs. She had a chronic deep wet smokers cough. She distributed warm Faygo red pop in 4oz Dixie cups to us from a tray, hacked up a lung and walked out shutting the door behind her. Byron paused looking at the door for a moment and said “she’s one fine piece of a**”, then turned to us and said “did I tell you boys that I walked with Hoffa”? “I walked with f-ing Hoffa, there’s the picture right there”. Pointing at an aerial picture of about a thousand tiny little people at a strike. I guess he was in there somewhere, and so was Jimmy Hoffa. Joining the union was useless for us. No benefit whatsoever, except for that story.
To answer your question, musicians do go on strike, but they play in symphonies not dive bars.