This absolutely doesn't explain C++'s weirdness. Those template parameters don't make anything faster, its broken seeding ends up pretty slow, and a Mersenne Tw

This absolutely doesn't explain C++'s weirdness. Those template parameters don't make anything faster, its broken seeding ends up pretty slow, and a Mersenne Twister is hardly performance- (or anything-)optimal. Heck, some of those template parameters are probably used by a sum total of zero people in production code.