Attempting to sabotage it maybe, succeeding no. There was never even so much as a stay issued, as far as I am aware, preventing the administration from getting started on implementation
Sorry, but even as an independent I would have to disagree with that. The statute provided monies for states to create their exchanges, there was no stipulated money to fund a federal exchange because it was entirely expected that states would want to control this themselves.
Suddenly GOP led states started saying "we're not building that" which makes absolutely zero sense except as a political stratagem to sabotage the process. You should note that the only two non-GOP states to leave the burden entirely to the feds are Montana and Missouri. Montana wasn't able to build their own because the GOP controlled legislature killed the governor's attempt to begin designing the exchange. Missouri is doing this for EXACTLY the same reasons.
The ambiguity over how many states the federal system would have to account for apparently hampered the setting of specifications (it would seem that most states needed custom integration bridges into the federal system) and severely impact the costs and complexity of the project (which was funded through means other than the bill.) It was always the goal of the statute that as many states as possible would manage their own exchanges - it was clearly not expected that the GOP would directly urge Republican led states to add their load the the federal exchange out of spite for the ACA. The irony is that this is the GOP asking states to give up authority to the federal government, lol.
You'll note that the states that did build their exchanges with the federal monies set aside for them seem to be doing ok, many of them exceeding their target roll-out goals.
It's also kind of silly to argue that GOP opposition hasn't made it more difficult and complicated to build, roll out, and run Healthcare.gov, I mean, simply ask yourself - "Would the healthcare.gov rollout gone better or worse with support from the GOP?"
The GOP is clearly doing everything in its power to have the federal exchange fail, and "doing everything in their power" doesn't mean just sitting quietly as you seem to suggest, it is actively sabotaging the funding and the process.
As for Democrats, apparently they ...couldn't build anything other than a good case of hemorrhoids.
BTW, totally agree with you regarding the 17th amendment - states lost virtually all of their ability to be effectively represented when this happened.