Hobby Games, depending on who you ask and where you go... actually have a decent chance of actually being completed. Just look up any "RPG Maker 2000 Games". Some of these are short and sweet with complicated coding. Some are rather long and extensive and have as many as five people working on them (FFEN is a great example). The trick isn't about getting a bunch of people to work on a game for you or help you implement some feature... The trick is obviously to get the creator to continue making the game. Many of us have other obligations and work at a snails' pace (job, bills, girlfriends, wives, children, husbands, our own games to play, etcetera). Some of us take what we've learned from previous games we didn't finish and apply it to the next endeavor.
If I had finished every game I started with this is what I'd have:
*A Pokémon game based on Pokémon 2000 in which you don't use the critters to fight for you, but instead take on a series of trials that mirrors the movie. A very poorly designed and thought-out game. The one hour playtime I ended up with wasn't even that fun.
*A game about a generic hero trying to save his kingdom from Dragons and being at war with them. Gameplay was decent, but the world map and story were severely lacking and not any interesting.
*A game divided up into "levels" that you could tackle with any character you liked (you were allowed to choose 4 classes out of 12 with 2 genders for each class). You spent Experience Points to gain stats and equipment. It proved too massive an undertaking with too many coding issues, so I scrapped it.
*A game in which I tried to code as if it were a Metroid game in RPG form. Battle flowed excellently, but coding events and designing landscape became a nightmare. Lack of a spriter (I can't draw at all, computer or no) also made a lot of the overworld stuff somewhat bland. Scrapped with the intent of trying again someday.
*A "Kingdom Simulator" game that worked a lot like Sim City in terms of operating your kingdom and expanding, but a lot like Ogre Tactics in terms of fighting and combat and all of that noise. I could never get the two concepts to mesh well in the way I had coded them so I scrapped the idea entirely.
The point is... Almost all of us here are "rank amateurs". We have no clue what we're doing or if we should do things. We've never made a game before. We've never gone to college for it and have no plans to do so. It's something many of us would love to do as a profession, but we're just absolutely clueless about how to go about it and lack the patience to learn some sort of computer coding to build something from scratch. So, we come and ask if a feature would be good or fun and sometimes other people will tell us why or why not. Sometimes, actual games even get completed on here. It's amazing a lot of games even see demo releases.
As for the comment about "players won't kill your NPCs out of morals, laziness, and fear of handicapping themselves", it's simply untrue. Give the player an option to do something, they'll try it at least once. Some of them will even do it more than once. All you need to do is watch people play GTA or Dwarf Fortress for honest examples. The reason people often don't kill an NPC is because it's BORING. It serves no purpose other than to stroke your own ego and to roll around in delight at your own maliciousness. It serves little purpose to kill most any NPC in a game because it isn't worth it to even do so. There is literally NO INCENTIVE to kill an NPC other than "I'm doing an Evil Run". I will grant you that most players will do a "Good Run" on a game. However, I don't think it's because they necessarily want to. They know what they're getting right off the bat. No matter what they do, who they kill, what evil monstrous acts they commit... They're still in the role of the Good Guy and doing Good Guy things. There's no option to join the Evil Overlord or to overthrow him because your plan is more awesome. So, why bother with the disappointment of an "Evil Run" when you're a good guy anyway? It becomes even more obvious that the "Good Guy" thing is railroading when characters stop liking you because you're bad and no new characters pop up to replace the people who hate you. Nobody shows up and says, "wow, you're awesome, I'm going to follow you around and help you 'cause you're so dastardly!". No reward for ever being evil. No point to it. So you get what... a few bucks from doing an evil quest? Is that really worth it? No. This is why a vast majority of players simply play Good Guys, it's a lot easier and it's far less disappointing.