Let's say you're right. That doesn't change that on this issue at least a democratic wave would be a win for society. Now you can argue that this is only because dems are corrupted out to corporations whose interests in this regard happen to allign with our own - you may even be right, but you're STILL wrong to claim changing the majority party can't fix this issue completely.
Even all that aside, if you believe that both parties are equally corrupt - you really, really WANT a system where the opposition party controls at least one house on the hill, the best way to stem corruption (especially in this hyperpartisan era) is to make it so it's absolutely impossible to pass any law without a significant number of opposition politicians actually agreeing with it.
That was how Washington used to work - in fact as recently as 2010 it's how things worked. Reagan passed his tax reform as a bipartisan effort that took two years of cross-party negotiation.
Obamacare took two years of negotiation with loads of input and ammendments, public hearings, things added and removed by republicans - and quite a few republican votes in the end.
Then came the "lets make him a one-term president by actively blocking ANYTHING he wants to do - even if it's something we wanted to do ourselves for years" thing (it had sort of begun with Obama's election but only really picked up steam after the republicans 2010 midterm gains allowed them actually behave that way).
Now I chose those two examples quite deliberately. They came from opposite sides of the spectrum, based on completely opposite ideas of how things should be done - but in both cases they were done slowly, deliberately, in a negotiation process that ultimately got most of the opposition on-board.
Thus far this year, both those topics have been up again. Healthcare and taxes. In both cases republicans have tried to fly-by-night the legislation, keep it secret until the last possible moment, done all in their power to avoid any public debate or any chance for even their OWN politicians to know what's in the law before the vote. This is what happens when a party has full control of the government and no longer gives a damn.
What's worse - their approach seems to be that they think they'll be forgiven any horrible thing they do, just so long as they "fuck the liberals". No need to govern the COUNTRY, no need to try and make decisions that benefit their districts, their voters or even their base - their base will be happy as long as they fuck those annoying liberals over.
Somehow, since 2010 - being willing to negotiate a decent compromise bill and acknowledge you're there to serve the ENTIRE country went from "how the good politicians do things" to "an act of treason we will not tolerate in a republican", somehow liberals, democrats, progressives and whatever else you want to lump in there on the left went from "fellow Americans I disagree with" to "an enemy that must be destroyed by any means necessary" , somehow they aren't "real Americans" anymore, and any negotiation with them, any attempt to consider their views is seen as giving aid and comfort to the enemy.
That's a recipe for a government that is not only wholly disfunctional but utterly incapable and uninterested in ever doing anything for the people that elected them - as long as you promise to fuck the liberals over, your seat will be safe after all.
So yes, this is a terribly bad situation and one-of-a-kind one that America has never seen before. It is absolutely crucial for the survival of America that Washington be taught that this is not behavior the electorate will tolerate or reward, that democrats win by a fucking landslide in 2018 - to teach republicans that this approach to governance is bad for their own careers.
Yes, a major victory by the other side WILL fix the single biggest problem in American politics today - which has fuckall to do with corruption. Sure corruption is bad - but it's teenaged acne next to the cancer of "the opposition are the enemy" that republicans embrace today.