Why is it, going up (being successful) is harder rather than sliding down(failing at some point)?

"success" is what you make it. What one person calls a success others might not.

Going up the ladder doesn't always involve other people. You might be talking about say rising to a CEO position from the position of mail carrier in the company...this kind of success has been accomplished by some people. But success can also mean you invest in stocks from your own home computer and become a billionnaire (from luck and knowledge and a sixth sense).

Sliving down would then mean loss of stocks from a bad turn in the economy or something happened in that company, so you'd get hurt monetarily. Losing success like from a higher staff position to a lower one causes embarrassment although it may not necessarily mean loss of pay, so it depends if your success is based on a title or on money. Losing success like from a higher line (management) position one just gets a bad name and has to leave with their head down. It's harder because of the expectations of society.