> It's an empirical fact that in all the years from the founding to the passage of the 17th Amendment the US federal government was much smaller than it quickly became in the years following its passage, so all of the available evidence is consistent with the theory.
This is appeal to history. We don't know if repealing the 17th Amendment would do anything at all like what happened 300 years ago.
> Moreover, the mechanism of operation makes logical sense. Senators want to keep their seats and state legislators don't want to have their own regulations preempted by federal laws unnecessarily and don't want excessive federal spending because money collected in federal taxes can't be collected in state taxes and taxpayers have a threshold level of total taxation they're willing to put up with
You are assuming a whole lot in that logic.
1. That state legislators wouldn't collude with the executive due to party affiliation
2. That spending more money at the federal level would require them to raise taxes
There is no logic or evidence when you get rid of the history and the wrong assumptions.