While I agree with jakebeal's answer, there is actually a reference about not putting any floats on the first page in
M. Shell, "How to use the IEEEtran LaTeX class," LaTeX class files, Journal of, vol. 8, no. 1, Nov. 2012
Note that, as far as I'm aware, the "Journal of LaTeX class files" is not a real journal but was just the default header of the IEEE LaTeX templates at the time this article was released. On page 8, under section X. Floating Structures, is the following quote:
Furthermore, IEEE journals never place floats in the first column of the first page and rarely (if ever) do they do so in the second column of the first page.
Unfortunately no further qualification is given as to why this is the case. Depending on how you interpret this it's either a hard and fast rule, a strongly recommended style guideline, or just a statement of the way things are in IEEE journals.
Either way it's highly likely that this paper, which most people download and read when they download the IEEE LaTeX template, has caused some authors not to put a figure on the first page. Combine that with the way the IEEEtran LaTeX class works and the fact that the first page is usually a literature review with no figure references, has meant that figures on the first page are quite rare nowadays.
Given all this the best thing to do is to contact the editor of the journal you are submitting to, to see what their preference is and just go with that.