15 handicaps don't shoot 3 over par. That's sandbagging and isn't really a reflection of the handicap system itself, but rather the people who utilize it.
I appreciate what you're saying, and typically speaking I opt not to play in handicapped events (unless THP is involved) because of that, but I don't think the system is broken. I stick to the people I trust and use our handicaps to have a fun competitive match with the caveat that loser buys the first round (and winner typically buys the second haha)
My latest tournament experience has me yearning to be able to compete in scratch tournaments. Competitive Golf in it's purest form must be so awesome, because strokes and the people who abuse them ruin it for everybody.