>>5
Building any large system that works is hard. Map/reduce isn't a solution; it's a dodge.
>>6
Moreover, object oriented data structures are extensively denormalized, duplicating information, and you cant make objects model every possible relation.
http://en.wikipedia.org/wiki/Database_normalization
Object orientation is everything that is wrong with modern IT. It is worse than COBOL.
>>9
The idea that there is a right way to design a normalized database–and that the wrong ways are provably wrong–is alien to most programmers.
Alien to most programmers lacking a university education, anyway. The root of the problem, I think, is that most users just don't care whether their software actually works as designed or not, so there's no economic incentive for programmers to produce good software.