I see this as a win for open source software. (Or "free software". I never know.)
Opera never open-sourced its rendering engine Presto, keeping it as a jewel of sorts. On the other hand, Apple always shared the WebKit code, so Google could come, fork it and make it better.
Opera thought that keeping Presto proprietary will give them advantage in the market. Instead, it made it obsolete and irrelevant.