You are correct, Sinn Féin didn't bring the government down for 2 years, it was 3 years actually.
Why did Sinn Féin bring down the government?was it because the NHS was in crisis, was it because of the state of the education system, the rise in homelessness, or the economy perhaps?.
The reason Sinn Féin collapsed the government had nothing to do with any of the above.
It was to force Westminster to impose a language act on N.Ireland costing 100's of millions a year.
Money that could be better used helping people, is wasted on trying to teach Irish to people who can't even speak English properly.
The City Hall had a dedicated Irish language telephone line for people who wanted to make complaints or enquiries about council services in Irish.
You could call and have your enquiry dealt with in Irish, they paid some ejit to answer the phone to other ejits who wanted to talk in Irish.
This fiasco cost 1000's a year, don't know whether it still exists, apparently the only calls they got were from pranksters in the pub.