Incorrect. They did want to win militarily. They failed utterly in that objective. Effective peace terms along the lines of the Good Friday Agreement were on the table in 1974, but the IRA and Protestant paramilitaries kiboshed them. The IRA then went on to pursue war for nearly a quarter of a century more because they didn't want civil rights, equality and peace, they wanted the Brits out and they believed they could achieve that by violence. They couldn't. Ergo, they lost.
British troops left NI 10 years ago so I would say the Brits are out. The leading figures of the enemy were then invited to the table and afforded positions of power in the democratic apparatus which hardly equates to military defeat. Be rather like offering Heydrich a seat in the The Cabinet.
You're conflating 'Brits Out' with 'Troops Out'. The troops were only there because of IRA violence. Once that stopped, there was no need for them. They left because they'd won, not because they IRA had beaten them.
They were offered seats at the table in a power-sharing government as a devolved part of the United Kingdom in return for abandoning the armed struggle, handing over their weapons and operating purely by democratic means. That was a million miles from their stated war aims of fighting the British until they gave up and left Northern Ireland to unite with the Republic and, as I said, was basically the same deal that had been on the table in 1974.
Let me ask you something: in a war, which side usually has to hand over their arms? Is it the winners?