You mentioned you have almost 11 volts on the purple wire. That wire should be on the starter solenoid small stud - it's the ignition trigger signal from the key (in a round about route.)
It appears that you have a multimeter, which is great, so verify you have B+ voltage at both the starter cable connection post, and within 1/2 a volt of that inside the car in the fuse panel. You can pick any hat all the time fuse in the fuse panel. If you have both of them, then confirm that you have your near 11v on the purple wire on the starter solenoid. If you have all of then the car should start. If it doesn't then you have one of 4 things - bad positive wire from the battery, bad grounding back to the battery, bad starter, or bad battery.
edit : forgot to mention, there definitely is a neutral safety switch on your car, it is located on the column as pagrunt mentioned. If you're getting near battery voltage at the purple wire at the starter, then it is not the issue because it's working.
It appears that you have a multimeter, which is great, so verify you have B+ voltage at both the starter cable connection post, and within 1/2 a volt of that inside the car in the fuse panel. You can pick any hat all the time fuse in the fuse panel. If you have both of them, then confirm that you have your near 11v on the purple wire on the starter solenoid. If you have all of then the car should start. If it doesn't then you have one of 4 things - bad positive wire from the battery, bad grounding back to the battery, bad starter, or bad battery.
edit : forgot to mention, there definitely is a neutral safety switch on your car, it is located on the column as pagrunt mentioned. If you're getting near battery voltage at the purple wire at the starter, then it is not the issue because it's working.