Turkey is not the sole issue of NATO.No it is just an issue with Turkey. And with this, they may indeed be wearing out their welcome. This isn't the first time they haven't been very helpful for what really benefits Nato.
Sadly, Turkey has really deviated from the ideals it once upheld. Its long and drawn out explanation, but Turkey in the 50s to 80s really wanted to be very European. Now we are left with a country that is going more and more to a more Muslin led bent, and at one point were actively trying to fight some US led efforts in Syria. They hate the Kurds as they lay claim to a lot of eastern turkey.
I would have think Turkey would have been bounced from Nato years ago if it wasn't for Turkey's absolutely golden strategic position. They control the only VERY NARROW Black Sea access. Which alone is worth its strategic weight in gold.
They also are a strategic "flank", They also have a big army. 2nd only to the US, in Nato. But its a mix of really modern stuff, and some older stuff too. But definitely enough to keep the Russians split and distracted while the main Nato force smashes eastward from mainland Europe.