It's not extremely slowly. We've been here for a 200.000+ years. Racism, at least in the west, is near non-existent compared to 60 years ago, let alone 200 or 2000 years. There will always be some form of discrimination. Either obvious or by someones definition.
But most forms of discrimination have long been accepted. Look at the 19th century: a lot of white men openly considered women and non-whites inferior. In that climate, you cannot expect change. So the 200,000-years timeline is a strawman argument, in my view. Only in the last few decades have the tides on those opinions definitely turned. But the actual reversal of discrimination in practice is lagging far behind. People aren't walking the talk. So yes, I do think change is coming far too slowly.
How many women are willing and able to do what it takes to be at the top? I'm not saying they can't. How many would sacrifice everything to be at the top of business? It's kinda hard to put a number to it. Is it 50%? No probably not. 10, 5, 2, 1, 0,1? What about men?
Coincidence? No. But why racism? Computer scientists. I'm pretty sure there's a disproportionate numeber of whites and asian, at least in the west. Is that racism towards black people? I didn't actually look at any numbers, think I've seen/heard it somewhere though. Pick a different profession if it suits you better. This btw would likely apply to men vs women also
I think that, in your examples, you are looking too much for explicit discrimination. A lot of discrimination, however, plays out on a subtler, societal level.
Consider coding: my pre-teen daughter currently loves to code: there are kids websites to learn coding, and she can spend hours on that. But as she grows older, she will experience a society where coders are nearly exclusively men, and where women are supposed to have different interests. This will shape her opinion on coding, and she might shift into something else. (As much as we might try to not let these things influence her.)
Or top jobs: the social environment at the top of many companies is very male-centric, in the sense that people are expected to have personality characteristics that are more common in men and that social forms often focus on behaviour most common among men. The argument 'do women really want it' does not consider that, and thus enters the discussion one stage too late. As a result, rather than considering whether the work climate is appropriate for all of humanity, the argument implicitly accepts that it's a white-man's world (pretty much saying 'it's just like that, what can you do?'), and takes it from there.
(Obviously, these are not cases of racism, but other types of discrimination; but I think the societal dynamics are the same.)