Unreal, Unity and now Source within just a few days from each other... It looks like the game engine market is commoditizing rapidly.
I have a (possibly crazy) theory: Companies like Valve and Epic have already amortized the cost of development of their engines - those are codebases that span 16 years, and both companies had multiple commercial successes. All it took was Unity to give a little nudge. Now, IMO, the reason for giving so much for free is to keep a player out (Unity) and milk the cow one last time with the eventual royalties. I think i…
We're in a perfect storm of access to development tools and interest in indie development thanks in large part to Steam and Kickstarter.
In the case of Valve, I think what butters their bread isn't Steam anyway, but the games people end up making with it that Valve get a cut from through Steam.