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Please see this as an interesting but not too significant data point about what's going in KDE, and don't forget that removing code is one of the finest tasks of a developer.
Of course these four million lines of code are only a part of all the KDE code that is written. There are tons of applications which are not part of the standard KDE distribution, but are just as great. Would be interesting to do the complete statistics, but this is hard. How to get hold of all KDE source code which exists?
Concluding random data point: SLOCCount thinks that it costs $ 175,364,716 to develop the code of the KDE core modules.