There's one factor the author forgot: persistence.
The best programmers I know are also friends of mine. But I pay them to do work for me. I could ask them to join me as a co-founder, but they would have to be willing to cross the Antarctic on foot to make the company succeed. Frozen toes, black fingers. It's something I would do, and I expect that of anyone with the title "co-founder". If they can't bring that (and that's hard to find -- I've looked), then I'll pay them, we'll remain friends, and I'll remain a single founder.
Investors are many, good investments are few. They might say they have rules, but they'll drop those in a heartbeat to be part of something good. In other words, I don't care about what investors want; I only care about making something great.
It feels odd that Y Combinator wouldn't fund single startups. If I wanted to apply for funding would I be better taking on a faux-cofounder? Of course I wouldn't do it, i'd just apply as me, but it feels false.
Putting it off on funding seems a bit odd. That's kind of like saying feet are shaped the way they are because otherwise they wouldn't fit into shoes.
If there's a bias against single founders from investors, it's likely to be rooted in them being less likely to succeed. If the opposite were true some investor would probably have figured that out by now and would be spanking his competitors who didn't have that rule.
More likely in their being less likely to succeed as big and as quick as the investors would prefer.
Also, from what I have read (mostly on HN), many VCs tend to be pretty control-freakish who often play-off founders against each other, which they can't do without co-founders.
I think often the term Startup is used in a way that confuses this kind of conversation and analysis. The term Startup, itself, really implies only that it's a new business. The word does not imply anything regarding the market or business model (i.e. how new vs. established each is). I think to many, especially in this forum, Startup implies innovative products in emerging markets using novel business models. Were this the frame of discussion, then I'd tend to agree that co-founders are important if not essential.
But, given a broader perspective of Startup types (i.e. the me-too crowd, or those with humbler aspirations than to be Googlesque) I think it's less true. That is, I think there are plenty of single-founder technology/web companies doing quite well.
It's not a matter of skillsets; it's a matter of communication.
Having a co-founder lets you bounce ideas off one another. It lets everything you do take on its own natural evolution. It's hard to explain unless you have a co-founder that you can easily and quickly communicate with, but I'll try.
You could compare it the show House MD. House is a brilliant medical mind, and much better than anyone on his team. Why does he even have a team, you ask? To throw ideas back and forth. When he can't access his team, he'll go to anyone to keep the idea in the air. He's even used a bum and an ex-con.
As an individual, you can train in all the skillsets in the world. You can become better at front-end, back-end, business development, selling, talking to people... everything. You can be even be better at coming up with ideas.
House, being fictitious, might be a bad example though. It's a TV show, so he needs a foil, how else are the viewers supposed to know what he's thinking? Besides, House is great because of the dialogue writing.
I'd say how good a programmer I am doesn't depend on whether I have company. Being a sole founder sucks because there's just so much to do and it's easy to feel overwhelmed, which means you can lose motivation very quickly, and there's nobody there to help you get fired up again.
It might depend on your personality - although you can be sure that you can be a good programmer 100% of the time, I know I occasionally make decisions that, in hindsight, are significantly stupid. Currently I can sanity-check things with my co-workers (or at least those of them that can spot signs of my stupidity) - if I were a sole programmer, that resource would not be available, so I'd either spend much more time checking my work, or end up wasting more time doing things the wrong way. Possibly even both.
If there were a lot of single founders with good ideas YC
might consider creating a new program called 2and20. If
your single founder application is accepted you have 20 days to get 2 additional founders and resubmit for a second approval?
I think part of it is that running a startup going for investor money requires similar social skills to running a startup with a co-founder. These skills are not required, and sometimes don't exist in the lone founder.
The big difference, I think, is that if you have all the equity, really all that matters is your will and ability to go on. Sure, your employees, friends, spouse, etc... are incredibly important, but dealing with a friend, spouse or employee is a rather different thing from dealing with a cofounder
FWIW, Pat House is a fantastic speaker. If you ever have the chance to see her speak, go. She was in the trenches during a very exciting and interesting time in the software industry, and besides for being a major player in the industry, she has a lot of interesting stories and insights to share.
Discounting here role as a co-founder would be a mistake.
Determination is intelligent stubbornness. Stubbornness by itself is how many startups run into the ground - as PG has noted, most startups change direction at least once after they get started.
The best programmers I know are also friends of mine. But I pay them to do work for me. I could ask them to join me as a co-founder, but they would have to be willing to cross the Antarctic on foot to make the company succeed. Frozen toes, black fingers. It's something I would do, and I expect that of anyone with the title "co-founder". If they can't bring that (and that's hard to find -- I've looked), then I'll pay them, we'll remain friends, and I'll remain a single founder.
Investors are many, good investments are few. They might say they have rules, but they'll drop those in a heartbeat to be part of something good. In other words, I don't care about what investors want; I only care about making something great.