Less appreciated by corporate titans and everyday borrowers alike is the massive changes in store if interest rates, abnormally low for the past 15 years, remain high for months and years to come. An entire generation of professionals has grown accustomed to ultralow rates, which translates into dirt-cheap money for anyone wanting to borrow. Low costs of capital, in turn, encouraged all sorts of dodgy behavior. Free or nearly free money drives business decisions that don’t necessarily take into consideration the need to earn a return on those investments.

If the rate jump were merely a hiccup — and many came to believe that’s what it would be — none of this would matter. But the reality is that the period beginning after the financial crisis of 2008 and 2009 is what was unusual. For most of modern financial history, U.S. interest rates, best represented by the yield at which the federal government pays to borrow money for 10 years, have hovered in the mid-single digits. The 10-year Treasury bill spiked at times — famously above 15 percent in the early 1980s — but generally hovered about where it is now, in the neighborhood of 6 percent. On Wednesday, the Federal Reserve left its benchmark unchanged, but left open the possibility of another increase.

Persistently high rates — Wall Streeters are calling the phenomenon “higher for longer” — would mean that the rules of business will look more like they did in decades past and less like in recent memory, when rates hovered below 2 percent and at times touched zero. That means that all sorts of businesses (as well as the U.S. government), which had gotten used to borrowing cheap and spending their loot willy-nilly, will be forced to scrutinize their decisions far more carefully.

Consider the streaming wars of the last decade. The starting gun of that skirmish was the release by Netflix of the series “House of Cards,” a breakthrough for a tech company that previously made money mailing out rental DVDs. Netflix carried $500 million in long-term debt in 2013, the year it released the series about Beltway deceit. By last year, that figure had ballooned to more than $14 billion. Yet interest costs on that debt amounted to a mere 2 percent of revenue, the perfect illustration of how cheap money enabled Netflix to fund billions in annual spending on movies and TV shows. That debt will become increasingly more expensive to refinance. Given that all of Hollywood followed Netflix down the streaming rabbit hole, the rise of interest rates is one powerful reason the entertainment industry’s spending will decline as it consolidates.

The 21st-century venture-capital business also was built on cheap money. Endowments and pension funds, unable to earn satisfactory returns in the debt market — the same phenomenon as retirees frustrated by meager returns in their savings accounts — flooded into VC funds. Venture funding grew tenfold from 2010 to $163 billion last year. The companies they funded could muddle along for years without earning profits so long as they grew enough to suggest that one day they’d earn money. That day has come to an end for all but the best start-ups, and overall VC funding undoubtedly will shrink as rates rise, or simply remain elevated.

One of the biggest debtors in the world, the U.S. government, has a problem, too. Payments on the national debt have nearly doubled in two years to $659 billion, making interest costs the federal government’s fourth-largest expenditure. And that was largely before interest rates began rising. There’s considerable disagreement over how big a problem this is given that the government’s overall debt-service capacity remains strong by global standards. But there’s no question that ballooning payments will put pressure on the federal budget, just as rising rates will turn up the heat on all borrowers.

This news isn’t necessarily all bad. The U.S. economy continues to grow robustly, rising at nearly a 5 percent annualized clip in the third quarter. Whether that growth lasts, it shows that individuals and businesses can adjust to a high-rate environment. But it will be an adjustment all the same, resulting in more judicious decisions by business moguls and lawmakers on the one hand, and car buyers and homeowners on the other.

Borrowers will look back fondly on the era of low interest rates the way middle-aged people consider their youth: It was good while it lasted, but it’s not coming back.