It isn’t about being full of ones self. No man comes to the father but through the son. If the Jews reject Christ they do not get a loophole. They are just like everyone else when it comes to being saved. Christ opened the door for all mankind, but you have to walk through the door.
You might also wonder about peoples who never had Christ preached to them (typically unbelievers use this as a objection).
Read Romans chapter 1 - it describes why all are without excuse.