1 (Single Founder) - people just ignore this one, more or less.
2 (Bad Location) - this one became a horrifying monster that devours everything it touches.
3 (Marginal Niche) - probably the biggest killer, then and now.
4 (Derivative Idea) - meh. People worry about this too much. Is there an unserved market?
5 (Obstinacy) - on point. Serve the market.
6 (Hiring Bad Programmers) - This one also became a horrifying monster. Graham says "In practice what happens is that the business guys choose people they think are good programmers (it says here on his resume that he's a Microsoft Certified Developer) but who aren't." Darkly hilarious in hindsight.
7 (Choosing the Wrong Platform) - meh. People use fucking backend Javascript now.
8 (Slowness in Launching) - Pretty valid.
9 (Launching Too Early) - maybe, I guess.
10 (Having No Specific User in Mind) - absolutely important. You have to be serving a market.
11 (Raising Too Little Money) - this pendulum has swung way over the other way now.
12 (Spending Too Much) - Yes. (Hiring too much. Stop trying to feel like an important funded company.)
13 (Raising Too Much Money) - Something of a subtle point, but still an important one - especially now that you can get too much money thrown at you more easily.
14 (Poor Investor Management) - of course.
15 (Sacrificing Users to (Supposed) Profit) - I'll just note that Graham writes that Google puts users first. Hindsight!
16 (Not Wanting to Get Your Hands Dirty) - Graham means with sales work. Very much true.
17 (Fights Between Founders) - This is why you vest, I guess. Graham was still down on founder vesting at the time.
18 (A Half-Hearted Effort) - I mean, why put in more of an effort if you have a route to fail upward?