If Apple wanted to, they could offer free tickets to everybody.

For example, 5,000 tickets at $1,599 each is just under $8 million, which is a drop in the ocean when you consider Apple has around $145 billion in cash.

While shareholders are rewarded with dividends and share buybacks for taking on risk, developers have to pay to take on the risk of building Mac/iOS apps.

$8 million represents %0.000055172 of Apple's cash. That looks to me like a pretty cheap way to throw a party for developers and celebrate all that they've done over the years.