I disagree with your point about the 17th. The ‘states’ didnt lose their Senators, the state party beauracracy lost their power over the Senators. The people of the states gained more control over their Senators.
Well, that’s one way of looking at it....
I prefer to go a few steps further in the course of events. The people having control of their Senators may be mistaken for the Senators controlling the people. They do this by providing benefits from the treasury.
The States are unable to stop this theft. To dismiss state powers as a simple bureaucracy is minimizing an important facet of government power. With the 17th, the States lost all official influence in the legislative courses of the US government (a very important point) and the Tenth Amendment lost its guardians.
Please consider these points; it was not just bureaucratic power.