Just as a point of information…
It is not the Federal OR State governments that set all of the rules regarding primaries. THe politcal parties set the primaries and the standards, and then the States have the opportunity to ratify those decisions (and if they do not, the Party can theoretically run their primary or caucus or whatever independent of the State Board of Elections).
NOMINATION primaries/Caucuses are purely a Party function. Some parties (such as the Libertarians) select their candidate at state then a national Convention w/o primaries (though the Libertarians have had primaries in some states in the past such as in North Carolina in 2004)
The order of the Primaries/Caucuses was set nearly a century ago, and it coincides with the removal of such things as Poll Taxes. Not sure if there is a causal link between the removal of poll taxes and setting 2 nearly 100% caucasuan states to lead off the nominations for both parties, but there is at least a correlation even if not a cause and effect relationship. And any change in the order of primaries/caucuses is up to the political parties. For example, the Democrats have fought to keep Iowa/NH first harder than the Republicans. When Michigan moved their Primary ahead of the national party mandate “earliest date” for non Iowa/NH/SC states of 5 FEB, then the DNC voted to strip ALL Michigan delegates oc their right to vote at the Convetion. The Republican party was not QUITE as severe and only removed HALF of the voting delegates, which is why Wyoming only had 12 delegates decided instead of their normal 24… they violated the “earliest date allowed” rule from the RNC and lost half their delegates (which went to Romney).