This raises an interesting question: Why don't more law professors write about state constitutions?

There are probably a bunch of reasons, but let me offer some amateurish speculation about just one. It seems to me that there aren't widely-known distinct theories of state constitutional interpretation. A lot of academic writing on federal constitutional law is about theories of interpretation. That subject tends to draw the most law-professor attention. But there doesn't seem to be a distinct set of theories on how to interpret state constitutions as compared to the federal constitution.

At least that's my sense from reading state court decisions, especially in my scholarly area of search and seizure law. State courts sometimes interpret their state search and seizure provisions as different from the federal Fourth Amendment. But they typically do so by simply reaching a different result using the same basic principles that federal courts follow. There are exceptions, but that seems to be the usual practice.

In my view, the most persuasive justifications for originalism at the federal constitutional level are not unique to the federal Constitution, but apply generally (or at least generally within Anglo-American jurisprudence).  So the originalism/non-originalism debate should be as relevant and interesting at the state level as at the federal level.  And I think there are interesting debates and developments going on (perhaps not sufficiently appreciated by federal-focused academics) in some states such as Utah and Michigan.  But I also think it's likely that there's less going on than there might be in many of the states.