Microsoft makes the talks from their conferences, like PDC, freely available few days after the conference.
Google goes even further by live streaming some of the talks (as in this year's Google I/O conference).
Apple can't seem to break free from their "top secret, control freak" approach even when it doesn't seem to make any sense.
I'm not even sure if they are free. There used to be a way to become register developer for free, at the lowest tier, but didn't Apple change the rules in the last year or so and you have to pay $99/year for mac developer program and $99/year for iOS developer program, so to access all the videos you actually have to pay $200/year?
All of the videos are available without paying Apple anything.
No. To access all the videos you actually have to pay $0, same as last year.