I've seen amazing progress over my lifetime, and I see enormous potential in current social movements. It's not guaranteed, and I see incredibly destructive social movements picking up speed as well, but I do believe it's possible.
From the time Lincoln was assassinated in 1895, until Roosevelt was elected in 1933, we had the age of robber-barons, enormous wealth disparity and the rich owning all of America.
We've had something like social progress from then until, when? Reagonomics? 1981.
So maybe 50 years of socially progressive government. Out of 250. Pretty dismal.
I think that there are many overlapping and mutually supporting systems that produce injustice (https://en.wikipedia.org/wiki/Intersectionality / https://en.wikipedia.org/wiki/Kyriarchy), so progress on for instance LGBT rights moves forward the broader cause of creating a more just society and makes progress along other axis more tractable. Eg, LGBT bigotry and the accompanying rigid gender roles provide a buttress for abusive elements in our society, for instance by telling men that an element of masculinity is to endure any hardship without complaint, thereby sabotaging their ability to recognize they are being taken advantage of and organizing to support each other in opposition to, say, an abusive employer.
I think people are starting to understand that our relationship to work and to resource extraction is untenable and that momentum is building. Of course this has been understood for a very long time, but anything remotely opposed to capitalism has been demonized and had almost no role in mainstream discourse (at least here in the US). I think that's changing pretty quickly.
On a long enough timescale, my confidence we can build a utopian society approaches 1. I think the trick is surviving long enough to get there. I suspect that a more just society is an attractor (https://en.wikipedia.org/wiki/Attractor). It may not be the only attractor, there may well be a totalitarianism attractor, but if we can get sufficiently close to the just society attractor we can get caught up in it's influence & remain stable in that state for a long time. Not by magic, it would take lots of work to maintain that society at it does to maintain ours, I'm saying society would reliably produce the people and conditions that allow it to maintain and improve itself. My diagnosis would be that our current society can create people with the ability to improve it but can't reliably create the conditions for them to succeed - but just because it isn't reliable doesn't mean it doesn't happen every now and again, so the trick is being able to make the best of whatever cards you're dealt and to stay in the game until you get a good hand.
This is mostly speculation based on my experiences and observations, I can't prove to you this is true (I can't, beyond a shadow of a doubt, prove it to myself). But it gives me hope, and I believe it reflects a truth about human nature rather than being a vain hope. So I offer it to whomever it may be useful, and if that isn't you, that's okay, feel free to discard it.
I have seen how fast any past progress can be reversed by sufficiently determined populist conservatives. Don't take it for granted when every liberty you have can be disappeared with one election.
> We can and should improve society.
We should, but what makes you think that we can?