America has a long history of protest movements. Many have real accomplishments to show for their efforts. The civil rights movement, the protests against the Vietnam War, the suffrage movement, and so on. The effects of the tea party protests are harder to measure. Their primary goal in 2009 and 2010 was to stop the passage of Obamacare, and, um, they failed. Other than that, one might assert that they had a broader goal of moving the Republican Party to the right, but if we look at congressional voting behavior, as Keith Poole and Howard Rosenthal have been doing (the guys who came up with those "NOMINATE" scores I always reference), that trend began in the 1970s, in which case the effects of the tea party are murkier.
And then there are the dumber protests. The "occupy" nonsense comes to mind. What was their goal? Something about a "conversation" about "inequality," if you remember the rhetoric, back when that was a thing. Has anything come of that? No. Why not? Because it wasn't a real goal. Desegregation was a real goal. Achieved? De jure, yes. De facto, um, less so. Ending the Vietnam War was a real goal. It was achieved. Having a "conversation" about "inequality" was a bullshit goal. That's why the "occupy" protests amounted to nothing.
The problem here is one that social scientists have been grappling with for years. Mancur Olson wrote arguably the most important work relevant here: The Logic of Collective Action. Ever hear of the "collective action problem?" He's the dude. That's the book. Participating in a real movement involves paying real costs. However, your contribution to the movement makes no difference in its likelihood of success, and if it is a real movement, you could lose something, so it isn't rational to participate. Scholars have been thinking about that for years. Focusing on the civil rights movement, Dennis Chong wrote... Collective Action and the Civil Rights Movement. His argument was that early organizers absorbed most of the initial risk, allowing later participants to join at a lower risk with a higher likelihood of success. Good book. Read it.
All of this is predicated, though, on a movement with real costs and a real goal to be achieved. These silly protests to get Trump to release his taxes have neither. They are feel-good events for the participants, who risk nothing and have no chance of achieving anything.
Here are the likeliest scenarios for us seeing Trump's tax returns:
1) Democrats get control of one chamber of Congress in 2018 after Trump does something stupid enough to cause a wave election, subpoena them from the IRS, and somebody leaks them.
2) Trump pisses off Putin, and Putin leaks them. (See what I'm doing there?)
This isn't even going to continue as a real issue. Trump is President. He is facing real issues, like Syria, North Korea, whatever happens in the economy over the next four years, the possibility of a state with no Obamacare insurers, and who knows whatever other crises, because crises always occur.
Some protests are bullshit. I'm callin' bullshit here. If you want to read the political science behind real protests, go read Chong.