I do not agree. The reason logos usually are expensive and take months: Because what else? If I have a multi-million Dollar marketing budget, sure the logo will take a good chunk of that, not only, say one permille (still enough to pay 5 designers for a week). If I want to change the perception of my company, I will not rush.

Does this mean the logo will perform better than one a design student made over the weekend? No.

Do many months of work prevent a failure? No.

In the end, Yahoo wants profit through revenue through site usage through loyal users. Does letter spacing have an influence on this? I doubt it.