The startups don't have this problem. Big corporations do.
What makes you say that this is not a problem for startups? Is it because you think startups are too small to profitably take to court and thus can safely ignore software licenses, or because you think that somehow companies below a certain size are incapable of evil?
Neither of them, all of them. Small companies, such as startups, are more concerned about creation: the team is strictly small, and it's fast responsive. Big companies have more bureaucratic practices and processes, and no one wants responsibility, there's more talk than getting things done.
"Corporation, n. An ingenious device for obtaining individual profit without individual responsibility."
- Ambrose Bierce
I wouldn't want to work with a company unconcerned about anything but creating things. Building cool stuff is awesome, but a company ignoring licensing issues isn't going to get very far. Regardless of that, I'm also an open source developer, and I don't take kindly to companies -- small or large -- who think OSS licensing restrictions don't matter.
> "Corporation, n. An ingenious device for obtaining individual profit without individual responsibility." - Ambrose Bierce
That quote is good for a laugh, but a lot of people actually believe that without thinking it through entirely. Corporations exist to limit legal liability to the corporation itself: So if a group of 10 people get together to do something, they can form a corporation, and the people won't lose their personal possessions if something goes wrong on the corporate level. Meanwhile, anyone who does business with the corporation is informed it's a corporation - in order to keep the legal protections of a corporation, the corporation must explicitly identify itself with markings of "Inc", "Co", "Corp", "Incorporated", or so on. When an officer of the corporation signs a document, he signs it as, "His Name, Pres." instead of just his name - indicating that he's signing in his officer role, not personally. People who do business with the corporation understand that if something goes wrong, they can sue the corporation, but not the individuals who invested in it and its employees, unless the people did something wrong as individuals as well.
Some people think this is a bad thing, but they ignore what happens if you didn't have them. If corporation limited liability wasn't available, established people would be muc more hesitant to go into a dangerous line of business for fear of losing what they already have. So you wouldn't have the most talented and established businessmen managing and investing in dangerous work like long distance shipping, mining, drilling, etc. Fields that are particularly dangerous would be populated only by people with nothing to lose - a scary proposition.
Actually, personally, I think the ideal is to make corporate limited liability weaker at the same time as generally having courts hold people liable less often. Currently, if you slip on ice in front of a business, you've got a decent chance of winning a lawsuit which is crazy. Spilling hot coffee. Etc. Reducing liability and generally admitting that "bad stuff happens and isn't always someone's fault" while simultaneously holding individuals more accountable when they actually do wrong would probably be the best legal mix. But, if you want lots of liability and broad judicial jurisdiction, you absolutely need to have limited liability in order to allow the most experienced people to get involved in dangerous and important fields without risking everything they already have.
As a practical matter I agree, but I think part of the general cynicism about corporations is that the Bierce definition so often seems appropriate. Even when a corporation is egregiously at fault in some matter, it's extremely rare to have the corporate charter revoked and the assets sold off. Sure, the shareholders could just go and form another corporation to do the exact same thing, but it would be massive inconvenient and thus serve as a deterrent from gross malfeasance.
What makes you say that this is not a problem for startups? Is it because you think startups are too small to profitably take to court and thus can safely ignore software licenses, or because you think that somehow companies below a certain size are incapable of evil?