As the tide of federalism ebbs away from the national government, its powers and responsibilities wash upon state shores. Furthermore, state legislatures are a critical training ground for future national officeholders. Congress are former state legislators. Many, if not most, governors and other statewide officials previously served in the state legislature. Unfortunately, state legislative elections today do not attract enough candidates.
Incumbents often face no opposition.
Potential challengers are scared off by the difficulties of a campaign against a better known, more politically experienced, well-funded incumbent. Even if there is no incumbent running, many qualified people do not want to undertake the very arduous task of campaigning. Yet some people do make the decision to run. They cross the threshold from private citizen to public candidate. It is not about the people who are already serving in the legislature.