Because the state has a monopoly of violence.
The only thing stopping me from just robbing food from a chain corporate store and redistrubuting it to everyone is the potential of going to prison (or getting shot on the scene by pigs).
Same thing with taxes.
I won’t be able to do this for long. Why aren’t we in the streets? What’s so great about your life that authoritarian rule is not a threat to you?
Ask anyone in an authoritarian country (that was already authorian before 2025).
One of the answer is: No one would take risks until there is nothing left to lose. Most people are not brave enough to take action (including me 😓 I'm afraid of the authorities). Survival instincts would overrule any desire to resist, its just the nature of living beings. It takes a lot of courage to even go to a protest, and much much more courage to revolt. There's a scale between a peaceful protest and a revolt. Not paying taxes is leaning 90% towards the side of revolt.
And many people still view the US as a full democracy, they don't see the backsliding and regression to a hybrid regime (or are in denial about it), and eventually, authoritarianism.
Some people are still trying to just "wait it out" until the next election. I'm not saying that this is right or wrong, but that's just some people's view on the trump situation.
As a Chinese-American, I'm particularly afraid that by attending a protest, if I get arrested, they would start blaming, not just Chinese-Americans, but also the entire Asian-American community.
Can you imagine how much more fucked this timeline would be, if the trump shooter was a black person, or hispanic person, or asian person, or some other non-white racial/ethnic group? (Or LGBT+, or any identity that's not a Republican Straight White Person) Magats would be rioting and burning down places. We'd have a "Bleeding Kansas" right now.
And its even harder for Asian Americans to find the courage to go protest, because there is often a lack of Asian American solidarity, where as Black Americans tend to have a stronger bond with each other in their community. Black American communities would encourage each other to take a stand, while Asian Americans don't have as strong of the sense of community. (I mean, I would get called a "chng chng" in class, and my classmates who are US-born kids of Chinese ethnicity, would just sit there and watch me get bullied, like wtf dude?!? stand up for your bros/sis)
TLDR: Most US Americans are just "waiting for the next election", because direct action is very risky.