Well, proof of what f0f said can be seen in the Wii scene; piracy was there almost from release, but it took over a year for homebrew to appear. The drivechips just fooled the DVD drive into reading pirated games, and the software security didn't help because the pirated games were correctly signed. Homebrew however had to get past the security. It's asymmetric so there's two keys, one of which can decrypt, and the other can encrypt things. Only Nintendo has the signing keys (good luck getting them without doing insane stuff!).
So they had to break the security by finding bugs in the software. Luckily with the Wii, there was more bugs than a bait shop.