A while back a close friend of mine asked me for some advice concerning how to talk sense to one of her son's friends, who was talking about joining a Satanic cult. I wrote this back to her, and it pretty much sums up how I would answer your question. Personally, I think that not all people are ready for adopting an STO mindset in this lifetime. This is because the path of least resistance is a seductive lure for those unable or unwilling to develop the necessary discipline. While initially easier, the culture of eat or be eaten becomes more and more difficult the farther you get into it, and it's sometimes near the end when a genuine understanding for some finally becomes possible.
While both paths (STO/STS) do have their purposes within this limited framework, it's quite clear that once past a certain point, the only genuine use for STS is to be used by STO to initiate action elsewhere. It's really that simple, since STS will generally move if it believes that there is an opportunity to feed, while STO can feed from ANY point of stillness...
Here's what I wrote:
First off, I'm going to say that I'm not a spiritual guru or someone who is even remotely interested in "saving" others, since it's not my job. Further, as a Gnostic, my definitions of Good/Evil Darkness/Light are significantly different than conventional/orthodox ideas but they are still deeply set within STO (Service To Others) principle. I would rather talk to you and your friend about this, because writing about it is really rather frustrating, as there are too many concepts to cover adequately. I'll do my best and try to "talk someone out" but understand that I'm more interested in giving them all the information needed to make an informed decision, and to clarify what such a choice really means.
I suppose if wondering what the point of staying on the positive/good/light path is, that would really depend on what someone's personal beliefs and level of awareness are first. The truth is that there are benefits and liabilities of ANY path, and knowing what you're getting into is far more important than blindly picking sides for any reason.
For example, if you don't believe in an afterlife, value only the comfort, power, and success of yourself and a small number of like-minded individuals, and have no regard for the needs of others outside your peer group or for society as a whole, you will find that going along a negative/evil/dark path to be much easier and more beneficial, provided that you can keep your intentions and acts within moderation, or if not, if you can at least prevent others from finding out the truth and punishing you for it. You'd be very surprised and probably horrified to know how many of our political, social, economic, and military elites are really truly debauched and perverted beyond what you or I would call acceptable, but if you take into consideration some of the choices that these people must make as a matter of course, then it really isn't all that surprising.
There are some problems with following this (what I call an STS - Service To Self) path - primarily that it's only valid if you TRULY believe that this life is all there is, and that there's no afterlife or judgment. If this is your truth, then it doesn't matter what others need/want/think/feel, does it? Your only real concern is getting caught, right? If you can get away with it, and if you can force everyone else to go along with it, then you "win!" A serious problem occurs when you come to believe that there IS more to life than what you can sensually experience, followed by ideas that there is more to come afterwards, and then the idea that you'll be forced to "pay" for your deeds in the next life will be a most certain and terrifying prospect.
You also have to take into consideration that the more enlightened perspectives such as charity, mercy, and tolerance are NOT a part of this path, (and are considered a fatal sign of weakness by your contemporaries) so you'll have to achieve your goals alone, unless you're willing to trust someone and grant them the opportunity to betray you if the person you're trusting ever realizes that they can, and you should actually expect them to if it's convenient and in their best interest to do so.
Another problem is that there is ALWAYS someone else who is bigger, badder, meaner, stronger, tougher, younger, older, healthier, hungrier, smarter, faster, richer, more spiritual, more psychic, more talented, more socially adept, more educated, more experienced, more magical, more ruthless, better looking, or better connected than you, and even if you do manage to get to the top, you'll find that getting there was the EASY part! Now that there isn't anyone left as a target to pursue, the new difficulty comes from those below you who see things the same way you do, and who now want what you have. KEEPING it is the hard part, and it insures that once at the top, you'll never have the opportunity to rest or relax to enjoy your position, because everyone else is gunning for you, and you're always in their sights.
This also means that if you were able to trust someone before, doing so from the top becomes impossible, and what's worse is that you never know exactly where the new threat is coming from, since you must now contend with ALL possible threats. This is the main reason why fools who get into power often lose it quickly, because they lash out at any perceived threat, which alienates everyone in sight, especially if their target happened to be innocent.
Remember that even the best people need regular breaks and time off, if only to protect their health. This is why so many high-powered individuals have heart attacks, strokes, and nervous breakdowns - they are too afraid to let go and it kills them. Then again, if you ever do get knocked out of the top, you'd better pray that the loss of station kills you, since you may find that once you've gotten to the top, lost it, and can't get it back, it's usually better having never been there in the first place.