Sure, but companies like SUN have huge automated testing suites that run after each commit, as well as gazillion of branches. And the author of the code is most

Sure, but companies like SUN have huge automated testing suites that run after each commit, as well as gazillion of branches. And the author of the code is most likely contributing plenty of those tests, if only in philosophical sense (by the hands of accompanying SDET). And whether you like it or not, the best companies rise and fall with geniuses. You can't automate them away. You can only accommodate them or they go elsewhere and you are done.