While you're right in those being reactions to a (correctly) perceived helplessness, have those things actually changed anything? I personally subscribe to Adam Curtis' argument [0] - from his works like Hypernormalisation and Oh Dearism - that they haven't changed anything fundamentally.
Sure, Brexit and Trump have had an effect, but are people truly better off? For all Trump's talk (whether you see that as positive or negative), I think we're seeing that even he's struggling against the whole system. And Brexit isn't really doing what anybody wants at the moment.
[0] Adam Curtis seems to come up regularly here on HN, for good reason. I can't believe it hasn't yet in this thread, but I'm happy to be the first. I strongly recommend all of Adam Curtis' work: https://thoughtmaybe.com/by/adam-curtis/