Will Ireland be invaded by the UK before 2030 in the event of a Sinn Fein Taoiseach in next elections
16%
chance
N/a if no Sinn Fein Taoiseach
Yes if afterwards and before 2030 UK (or a successor state) launches a military campaign to occupy territory on the island of Ireland not currently within Northern Ireland.
See this article for an argument that it may happen https://www.rte.ie/brainstorm/2022/0511/1297303-ireland-britain-sinn-fein-conservatives-imperialism/
It's probably even worse than what you say given there's not going to be a 100% chance of a Sinn Fein Taoiseach before 2030 anyway, so it's not just the lack of monetary interest that is causing this.
This market is interesting, because it illustrates a case where it is very unlikely that its price accurately reflects the sentiments of market participants. I'm sure someone has come up with a clever name for this, and, thinking about it, I guess it probably applies in non-prediction markets as well.
The issue arises when a market is a long way from expiry, and is moderately but not extremely mispriced (say, 10-20% away from the real price). At the time of writing, this market is sitting at 16%. Idiotic clickbait headline from someone who should know better notwithstanding, I'm sure that the vast majority of people would put the chance of this resolving 'YES' within a rounding error of 0. So, why isn't the market lower?
The mechanism for correcting the price should be that I can profit by doing so. There are two ways I can make money by correcting a mispriced market:
First, the market can resolve in my favour. This will happen here - but not for another eight years (because I'm betting *against* the event occurring, I have to wait out the clock). Even for real money, 16% over 8 years is a poor return; it's just not worth the opportunity cost. So I won't be hodling my short.
Second, I expect that lots of other people will agree with me, driving the price down, after which I can cash out early -
effectively, the 'greater fool' theory, except that in this case I *agree* with the other participants about the 'true' value of the market! However, for this to work I have to feel that I either have some 'special' or inside knowledge that means I'm better placed to recognize the mispriced market than every/most of these other chumps, and get in there first. But this question is so obviously 'NO' that no-one outside of Boston could honestly bet YES (and, so far, no-one has). So, I don't think there are going to be any greater 'fools' to take advantage of. So I can't cash out early, so I shouldn't bet.
And thus, the price asymptotally approaches an artificial floor of the 'real expected probability' (i.e. 0-1%) plus the opportunity cost of holding till 2030, plus some minor bonus of 'greater fools' getting out early - because after a certain point, it's too expensive to pick up even the free money. If I'm right about the expiry being an issue here, I'd expect the price to start dipping again when we get much closer to 2030 (assuming this market and this website still exist then...) when people start seeing the opportunity of quick & easy returns.
So, is this a 'failure' of the market in that the price doesn't accurately reflect what people think the real probability is? Or is this just how markets are expected to deal with long-term contracts, and I should be a lot less certain than I am? I'm going to write up this scenario in a bit more detail and then go and ask some professional commidity traders if they see this play out in 'real' markets.