Investors like cofounders because they don’t like betting on people who either think they can do everything or can’t work with others. Why? Because starting and running a business is really, really hard—-there are many things to do all at the same time—-and the software or other technology is only a small part of job. Solo founders are just not very likely to succeed. There is too much risk. Oh, and “finding” a cofou…
If you happen to find a good cofounder or a good spouse, then you don't keep changing them. That team is worth more than the current venture.
The problem of lacking a cofounder is lacking another pair of eyes and another brain who can help moderate wacky ideas. Everything seems like a great idea and a utopia, in isolation. But in the real world, some ideas are better than others. No one person can think of everything exhaustively and can prioritize it.