Yes, incumbency has advantages, but it doesn't make a Senate or House seat bulletproof. And remember that House members run every two years, which basically means they are running for re-election constantly.
The reality is, of course, that America is doing pretty well, thank you, even with these awful "incumbents" trying to ruin it. Inflation is at an all-time low. Mortgage rates are under 5% as is unemployment. Incomes are going up. The stock market has been on an eight-year tear. All things that Trump will claim credit for, even before his inauguration, of course!
If these incumbents are screwing up America, they are doing a pretty shitty job of it.
With regard to "social issues" the folks in the House and Senate are not really responsible for that at all. The gay marriage thing was done by the Supreme Court, and Congress can't overturn Roe v. Wade anymore than it can pass a law making Pi equal to three.
So the premise is flawed. America has the strongest economy in the world, and no, we aren't going to hell in a handbasket, even under President Trump. Well, let's hope, anyway.
The fifth problem is that term limits would have deprived us of some of the best legislators in our history. Legislators such as Daniel Patrick Moynihan, Tip O'Neill, Bob Dole, or even Newt Gingrich would not have had the impact they had (for better or worse, depending on your views) if they had served only one or two terms.
The major work of the House and Senate is not accomplished by the newbies, but rather those old "war horses" who have been around the block a few times and know how to get things done, such as by compromising and making deals.
Legislating, like sausage-making, is a process best not observed, the old saying goes. Often odious things have to be done to get things done, and idealistic one-termer tea party types couldn't stand for this. The "my way or the highway" attitude is what got us into trouble in the first place with gridlock in DC. But again, we have to question the premise of even that argument as....
The sixth problem is that Americans actually want gridlock. The idea that "nuthin' is gettin' done in Washington!" is somewhat flawed to begin with. Budgets are passed with regularity and the only time this doesn't happen is when - you guessed it - those "term limit" tea party types decide to shut things down.
But sometimes getting nothing done is a good thing. The status quo is often the best place to be, as it likely is today. Constantly meddling in our nation's legal and regulatory system is often a bad idea, as it provides no consistency or predictability for individuals and businesses. Small incremental changes are usually a better idea. The real tragedy of Obamacare is that it forced everyone to change their health care plans for a couple of years and now we will be forced to change back - to what we don't know. People and markets prefer stasis to radical change every year. Obamacare might have survived if it was more modest in scope or phased in changes over time.
Americans, with regularity, often elect a President of one party and a Congress of the other. Even when one party controls the White House and Congress, often little gets done due to bickering, deal-making, and just general disagreement. If Trump thinks his tariffs and term limits will even get a vote from McConnell and Ryan, he is sadly mistaken. Even with the GOP "running everything" a lot will not get done and that is probably just as well.
Sometimes, the best thing Congress can do is to do nothing.
Term limits are not an answer to anything. They are a favorite whipping-boy of the far right and the libertarians. But it never is made clear how term-limits (like the gold standard) would fix anything at all, much less "everything".
Rather than embracing simple solutions to complex problems, I would suggest a better idea is to better understand complex problems - from all angles -and realize that complex problems often require complex solutions - solutions that can't be explained in a sound bite or in a slogan.
Stop thinking in Tweets and bumper stickers - if that can even be considered "thinking".
Term limits are not the problem with America. The problem with America is that 90% of the population can't think in terms of more than 140 characters. 99% of Americans couldn't even read as far as this sentence.