It depends on what kind of effect you’re expecting. Did the US state and federal governments suddenly defund the police and start sending reparations to black Americans? No, not exactly. But Derek Chauvin was convicted and sent to prison for 20+ years. Different municipalities did reform their police departments and even implemented things like unarmed crisis response units. BLM has helped introduce policy discussions that would not otherwise be on the table.
The effects of a protest aren’t always direct or immediate, their benefit is as much about changing the national narrative on any given issue than it is just achieving a primary goal by the time the protesrs end, and also it’s a way to learn what’s effective and what’s not.
For example, part of why these recent protests were effective and why they illicited such a desperate response from authorities and the media is because the young people looked at the failed tactics from protests like the Occupy movement and adapted.
One if the weaknesses of Occupy was that there was no unified voice, instead the media would walk up and find some random individual, get them to make some unflattering soundbyte and then put that on blast on their networks. By contrast, the students anti-genocide protests designated a spokes person, and when the media approached random protestors they would just direct the media to that spokes person.
It’s really smart and that kind of tactical refinement is arguably a result of the failures of Occupy. It made it difficult for the media to fool the public as to what these protests are really about, and you see that born out in people’s growing awareness of how fucked up the situation in Gaza not only is right now, but has been for decades.
Protesting and social justice is iterative and experimental, it’s about making it more difficult to just continue with business as usual going forward.