The landscape will change for sure - I predict highly skilled contractors will only be engaged to the larger firms via the big consultancies, who'll end up fighting over each other for good people with particular skills. Those who don't go down this route may have to reduce their rates to work with smaller firms who aren't in the scope of IR35, or go perm. I can't imagine many will go abroad - I've noticed remote work roles in northern Europe come up increasingly often, and I expect this will happen more with the surplus of skilled people in the UK. Some clients will look overseas to fill the skills gap, wiping out tax revenue in the UK: that could swing back in a generation when government wakes up to this wilful act of self-destruction.
Personally, I'd advise making oneself as indispensable as possible to someone with a large budget and tight deadlines in the next few months.
Still, there are a quite a few contractors I've worked with in the past who are not highly skilled, pleasant to work with or even decently competent. They're the ones who should be worried about April.