Are highly rational individuals more sucessful?

In my humble opinion, no. Here is why, I think a strong emotional quotient can matter more.
Successful people knows that the core of any achievement will depend on personal relationships.
The most successful people are frequently unreasonable people who refuse to give up, even when evidence and odds are very much against them. In conclusion, human skills are more important than cold rational logic.

Measurement of ROI for EA?

ROI (return on investment) for EA(enterprise architecture) is too difficult to measure. We can probably measure nonfinancial or nontangible benefits like stakeholder satisfaction, but turning these to money is just nonsense. However, we can show the logic how EA contributes in company goals.