Check when the flight arrived in IST and how that connection looked in the end. TK flight can make up a LOT of time TATL, I have seen them make up 60-70 mins ... schedules are quite padded. TK can also re-book on other *A carriers, did you ask at the airport? I had an YYZ-IST-NRT flight with a 70 min connection and the YYZ-IST flight was 120 mins late - yep, that one was not going to work out So I asked TK and they rebooked me on AC YYZ-NRT direct - no questions asked and hotel provided as well.
I checked how the flight did in the end and it arrived 50 mins late (made up 70 mins!) - would have still misconnected.
So yeah, if you voluntarily 'cancel' without exploring re-routes are seeing if the flight makes up time - that will be a hard argument to make.