[A93141]

  the assumption that share-alike encourages contribution is a myth

OpenWRT is the biggest counterexample I know of. Linksys would not have released this if they had been using a BSD licensed operating system.

If you want to work on an open source project, but your employer has a restrictive intellectual property agreement, then a share-alike clause can be the only thing allowing your work to get out at all. You can show your employer there's no way they can subvert the license agreement, and if they distribute it at all, they must use the same copyleft license.

I don't want to see my hard work sold large-scale in consumer electronics, just to enrich others, without contributing back at all.

[1ris]

Or a free Objective-C compiler. Or free software for IBM computers. Or drivers for Linux.

[exelius]

I think there's a distinction to be made between a data set and executable code.

[dTal]

What would you say is the precise nature of that distinction?