TLDR: Strikes work.
The first strike I organized was in 8th grade. The two strongest girls decided to arm wrestle in the cafeteria, and everyone got pretty rowdy. The school's response was to call it a “riot” and put us in assigned seats for lunch, alphabetically. I went to my friends and suggested everyone stop buying lunch in protest. We went from table to table, getting people to commit to packing their lunch.
See, at least in my district, schools were required to make enough lunch for every student. My class was about 350 kids. The first day of the strike, maybe 20 bought lunch. Every day after, it was more like 5 or 6. Each lunch cost $2.25. Then there were a la carte items like soft pretzels and (most importantly) Krispy Kreme donuts, which were $2 each.
Every day, we could see them throwing away trays upon trays of food. Teachers were taking home industrial trays of lasagna. The vice principal went classroom to classroom giving donuts to teachers, because they could not sell them after a certain period, and the contract had them receiving more whether they sold or not.
Over the first two weeks of the strike, they held two assemblies to tell us we were behaving badly. That only good behavior would get us our seats back, and the strike showed a lack of maturity. That we would have already gotten our seats back, if only we hadn't done this. The second assembly was much more desperate on their part, and they took away our outdoors time as a punishment. But we were all in it together.
After the third week, they gave us our seats back with no fanfare. The punishment was just over. This, despite repeated threats that we'd be in assigned seats for the rest of the year. But we were all in it together. And more importantly, we'd done the math.
If students only bought the standard lunch, we were costing them over $700/day, putting the minimum 3-week total at $10,500. But the donuts. They would sell out every day pre-strike, so that's conservatively an additional $1,500 total, plus drinks, bagels, pretzels, etc. We had pizza day on Wednesdays, which was delivered from a local place so 3 Wednesdays would also probably push the total up.
My history teacher was a former coal miner, and he teared up while talking to us about it. Said that we picked the absolute dumbest thing to strike on, and he hoped we would apply those efforts to something besides a minor personal injustice in the future. But that he'd seen grown, Union men fail to organize the way we did, and that we should be turning our eye to protesting real problems, no matter our age.
The point of this story, is that we were 13-14yo kids in a suburban school being threatened by our principals, having letters sent home, and risking extending our punishment for months. We also didn't get to eat pizza despite the amazing smell, or donuts, or chocolate milk. If we want to, we can change the way the world works. We can say, “No”. If we do, then we will be threatened. We will lose things. We will feel like it's not enough to move a giant corporation or government. But every single organization and institution is made up of people. And people do not like to look bad or feel bad.
Lastly, if you ask most people who were there, they won't have any idea who started the idea for the strike, or who told them. When reminiscing with old classmates, the word “spontaneous” is often used. It was not spontaneous. If we want people to act, we need to sell them on it and get them to commit.