If the Chinook had not crashed on the Mull, that is what would have happened to the main body of the IRA itself.
Then the people (north and south of the border) would not have been subject to a process which has de-nationalised both communities leaving them both exposed to externally dictated policies on the economy, immigration, etc which has been destroying both cultures, bringing them into line with the mainland.
Do not confuse the mainstream IRA (which has had internationalist backing) with the weaker but genuine nationalist "splinter" groups - horrific though their acts are, they are ineffectual compared to what the mainstream IRA has been able to get away with and reflect the level of terrorism that could have been expected had not some very powerful interests wanted to keep the "troubles" a running sore to destabilise a part of Britain that was hanging on to its culture and its local sovereignty.
Airey Neave knew what was going on and was going to do something about it ...