That would be a rather negative essay and it would not be any productive. Instead of talking about people who should not, we can keep talking about people who should or skills to acquire prior to starting a startup.
Here's why I disagree with you (I upvoted you because you make a valid point worth debating and weren't an asshole):
There's an instinct in us all to assume that because people are good/talented/interesting in some ways, they must be good/talented/interesting in every way. On Hacker News and in the YCombinator sphere, there is a blunt attitude that if you're at work and not starting something up, you're not being as productive as you could be/are wasting your life. This gets reinforced by everybody here, not because people are assholes about it (most of them are not), but because everybody here is so well-spoken - and most everybody here is wise and talented to boot - that it's easy to look at this crowd and say, "These people are people I like, and they do startups, and because I don't want to do startups there is something wrong with me."
Paul's essays reinforce this. Because he constantly writes from the assumption that yes, building a start-up is good, his essays have slowly taken on the attitude that the Paul Graham way is the right way, no shades of gray. The thing is, from his perspective I'm certain it is the right way. He doesn't bother writing essays for people who don't have his same mentality, and he shouldn't have to frame himself in that way. But the Hacker News mentality is so wholly wrapped around "PG"'s that very often it seems his essays define what's good people and what's bad people here. So if you're not a start-up person, there's something vaguely hostile in that set-up.
Sometimes, thinking about what advice you're giving should not be followed is the most productive thing you can do.
To the OP: My advice is to look for that knowledge somewhere outside of Hacker News. As bright as this community is, it's a very one-sided one and it's that way for a reason. If you want to round out your opinions, look for other communities that aren't so focused on the start-up mentality, and stay there until you build up confidence and realize that in the end, you get to decide what matters to you rather than other people.
Excellent points and very well said. Recently I have been starting to feel down about myself and I noticed that it had to do with reading Hacker News and estimating my value through the lens of this startup value system. Despite the obvious talent and intelligence in this community, as you pointed out, if you are constantly face to face with a value system that is at odds with yours you will either (a) decide that it is not for you and walk away or (b) if you are of a more impressionable mindset, you may start to wonder why you don't match up. In my case, I have been finding the latter, at the expense of my self-esteem. So perhaps, as you suggested, I should take a break from HN for a while, as seductive as it is both in terms of content as well as the quality of the discussions.
I found myself going through faces of obsessive determination and complete apathy last year. I think part of that's probably just life: Everybody runs into dilemmas. In cases like this, where partly it's a matter of being online talking to a focuses set of people, taking a few months off works wonders. Turn on noprocrast, set your away time to 65536, and figure out what else you can do. I just got access again a few weeks ago, and I don't feel the pull of this community anymore, so I don't feel as committed and frequently hopeless. With luck something like that could help you out as well.
(My other, snarkier advice is to go to Metafilter and look at every thread regarding a Paul Graham essay, because Metafilter's a bright community that loathes Paul Graham. My opinions are somewhere in between there or here, but reading those threads in June was rejuvenating in some ways.)
But I'd add one note of caution: hang out with people you want to emulate, even if you do a piss-poor job of emulating them.
If you want to learn chess, hang out with chess-players. If you want to learn writing, hang-out with writers. The outstanding members of these communities will always kick your ass when it comes to execution -- that's the nature of large communities.
The real question is whether you can be brutally critical of your work and life and strive to be a top notch player while still having a happy and joyous lifestyle. Some people can. Some people can't. If you can't, then your options become more limited.
I look at it this way: whatever I'm doing, there are lots of people much better than me at it. There are lots of value systems both for and against what I'm doing. It's up to me to chose a value system and honestly learn from the masters to really enjoy life. If I do a half-assed job of either I end up miserable and unhappy.
Hacker News is probably the last place someone will get advices about not starting a startup. It was named "Startup News" to begin with, hence its Pro-Startup audience.
The reason why people here push others to do a startup is because they are doing it themselves and find it quite rewarding. Not necessarily a monetary reward, but a personal satisfaction. If they see potential in someone, then it is normal to ask "Why not give it a try?".
Also I do not believe anyone ever left their extremely satisfying job because commenters push them to do so.
Apparently 20 venture capitalists told the Skype team they were not going to fund them. They were all wrong to the tune of 3B dollars and 10 millions simultaneous connection as of this writing.
This is why I am still confident PG or any investors can make a good judgment about who should start, but not who should not.
In the end, no one knows.