We needed the lesson that there is nothing we can do to be saved except to receive Him by faith;
"Lord, remember me"
and have His personal answer (by the indwelling of the Holy Ghost)
"This day thou shalt be with Me"
Yes, it IS that simple.
God did not pat us on the head and say, "Good luck kid ... hope y'MAKE it"
Also, the thief did not look down at Mary and ask, “Will you petition your Son to let me into paradise with him?”