I think there's a mix of things - as I may have mentioned a mere 3456321 times (although that includes in other places online and at work and in person,) I was at a BBC Women in Tech event on Friday - they have about 150 vacancies to fill by next year, and they said they're struggling to fill them - the skills they want just aren't out there in enough numbers. They are particularly targetting women, because it's harder to get women to apply - all the stuff about women only applying if they match 80% of the spec and so on. They've also seen that different job titles on the same job spec make a difference to the number of women which apply.
I think also there is a bit of an increase in tech vacancies anyway, plus we do have a general issue with the skills requirements in tech - a lot of roles do need specific skills, which means that someone somewhere needs to offer training, but recruiting companies usually hope it's someone else doing it, unless it's a graduate scheme or similar.
But as well as all that, diversity is very much flavour of the month, and unconscious bias in particular, from what I see. The risk of future C-suite quotas is probably only a small factor; I think with my employers, it's responding to reports that more diverse workforces is generally positively reflected in profits - and in the end, shareholder value is what they care about. I'm under no illusion that if some research proved white male-dominated companies perform better, all the inclusive policies would be out the window.
(Have to say in my tech role, enquiries from recruitment agents are fairly steady, but development roles tend to be more prone to the economic climate - you have to keep existing hardware running, but you can hold off development of software updates for a while.)