I still think you're placing entirely too much faith on disparate state and/or regional interests. In actuality, the country is now operating very much similar to the Union vs Confederacy. CA, NY & IL (and their satellites) cooperate (and think) very much in the same manner, with the same goals and objectives vis-a-vis competition with, and the desire to defeat, conservative (red) states.
Secondly, I'm a bit confused why state/regional economic interests would have any bearing from the impact of post-17th dispersed state-wide appointment. All economic sectors benefit from government subsides and direct demand. As to the topic at hand - that is, endless war - there's not a segment of the economy anywhere, in any state, that doesn't benefit from military demand. Oil, coal, food, high-tech - you name it, everyone has a hand in the pie.
The same money flowing from the same special interests would be directed towards a few state representatives is a few potential swing states. Secure 50.1% of 26 states, and the Turtle has got the same exact platform.
Again, it's not a piece of paper with laws, rules & regulations written down that governs conduct. Rather, it's the people themselves and the expectation they demand from representatives. If the people themselves are so entirely co-opted, then the republic is dead, and we're operating in a post-constitutional environment.
I think state legislatures are more likely to select one of their own rather than a beltway creature.
I think a state legislature might choose a "favorite son" industry leader to be Senator if the dominant industry is the main economic driver of the state. They get to select two, so why not pair a legislator with a key business leader?
I think a selected Senator is less likely to assume they will stay in DC for as long as they want or as long as they can fool the distracted voters.
I think that state legislatures need to make Congress align with what the states do. Currently, the states are forced to accommodate what Congress does. Congress does what aligns with party donor bloc interests.
I think that state legislatures work day in and day out on the nitty gritty details of local bills affecting the state voter, and it would be in the best interests of the state voter to let the legislatures select the most knowledgeable and influential people to represent the interests of those bills in Congress.
I think that the logistics of controlling dispersed statehouse politics is far more burdensome than working through few dedicated DC lobby groups managing a few key Senators. Those "leader" Senators who distribute the spoils downward makes it easy. That would go away.
I think a sitting Senator cannot abuse a repealed 17th amendment by refusing to vacate their seats. This is a structural amendment with no wiggle room for interpretation or abuse. If they're not appointed, they go home.
-PJ