They're idiots. IIRC the choice between House Speaker and Senate Majority Leader has waffled back and forth over our history, depending on party control of the Presidency and the two Congressional branches; the current system came in and has stayed undisturbed because switching it with the political winds proved to be just too divisive and a political battle in itself. Of course the Speaker will have had to be elected within the past two years, and the Senate Majority Leader could be almost six years in office at any given time, so there is an argument that the Speaker would be more in touch with current political winds (Which is actually a stupid reason, since in both cases they'll be from jurisdictions that have re-elected them time after time in order for them to have accumulated the necessary seniority to reach those posts, so there is nothing contemporary about the beliefs and orientation of either one of them).