1. Who has a computer that's never online?
You can use an offline linux live CD rather than an entire computer
2. How many users are aware of the risks?
The more Bitcoins a user has the more likely he will have educated himself about the risks.
3. How exactly do you send a transaction from an offline computer? Could it be that it's complicated?
You can use an offline smart phone, or camera to transfer unsigned transactions using QR codes, or you can use a flash drive to transfer files containing unsigned transactions.
Your online computer creates an unsigned transaction. You transfer that to your offline computer using a QR code or flash drive. Your offline wallet signs the transaction using its private key. Afterwards you transfer the transaction back to an online computer using a phone/camera/flash drive, and broadcast it using your online wallet.
It's safe because your offline wallet's private key is never exposed to the internet.