Complex sentence: Those who fail to show the skills that all must know and be able to do for any college or career will forfeit their diploma, and be be barred from any high paying job because they do not meet the standards of the 21st century.
Split into simpler sentences: Those who fail to show the skills that all must know and be able to do for any college or career will forfeit their diploma. They can be barred from any high paying job because they do not meet the standards of the 21st century.