Different number of candidates, and different situation.
There were twice as many candidates divvying up the vote, and general elections bring in more voters.
No comparison reasonably possible. IOW your claim was a ridiculous red herring (and wow am I surprised).
In the Nov 2012 Texas election for US Senator, there were 6 candidates on the ballot but only 3 received a significant number of votes.
In the Nov 2012 Texas election for US President, there were 7 candidates on the ballot but only 3 received a significant number of votes.