It has also done the same for lot of people in the rest of the EU who before believed the same far-right populist fables about how great it would be to leave the EU, which is why the far-right in those countries doesn't talk about that anymore.
I lived in a couple of countries in the EU and my impression was that Britain was the best candidate of all in the EU to fall for the whole "We would be better of outside the EU" because they were the ones who looked back to the years before entering the EU and mainly saw a great Great Britain (an image relentlessly beautified and pushed by local media right, which is why even now almost a century after it a "new British film coming out about how Britain pretty much singlehandedly won WWI" is still a regular event and news about international affairs in Britain tend to be either spinning Britain as having great influence in the World or "look at that tupid thing happening in that country, this would never happen in Old Blighty [as we're superior to those foreigners]" news pieces) so it was easy for such Delusions Of National Greatness to be turned into Brexit by outside influences (namely, American - just look up who funded Cambridge Analitica to spread pro-Leave propaganda).
After the subsequent shitshow with the "most likely nation in the EU to fall for Alone We're Stronger bollocks" none of the larger nations left in the EU (which are just mid-sized nations in World terms) have any illusions that leaving would make them better of (plus people there already had fewer delusions of greatness to begin with than Brits), whilst the smaller nations never had any fond memories of time before the EU when they were little more than kicking balls for the bigger nations, to begin with.
All this to say that the country were an EU exit was most easy to leverage by foreign interests has already had that happen and the result stands as an example that further deters the idea of leaving in the few EU countries were the idea that "we were stronger alone" ever had more than a handful of believers.
