As @ChrisF correctly says, landing too far towards the end of the slope, hence towards the end where it becomes less steep and less parallel to the flight path of the jumper, would be very dangerous.
In ski jumping, every jump and slope is designed for a fixed jump length. This length is given by the K-Point which designates how far at most the contestants should jump. Up to this point, a safe landing can be achieved by any well-trained contestant. Landing beyond the K-point is dangerous. Or rather, it would be.
According to the rules, before the contest, the jury decides on the length of the inrun, taking into account the state of the jump, the weather and in particular the wind, thus making sure that the chance of contestants landing beyond the K-point is minimized.
Also, if one contestant reaches 95% of the jump length, the jury will interrupt the contest and decide whether the inrun should be shortened.
Note that there's quite a lot of additional rules about the equipment of the contestants, including details about the suit and the skis, which ensure that the jump widths in one particular contest tend to be somewhat predictable.
So, it's the rules that ensure that ski jumping on a carefully constructed jump is not suicidal. In fact, jumping on your self-built jump might be more dangerous than any jump you see on TV.
 Don't ask me what happens to the contestants that have performed their jumps up to that point in time.