Much has been made of Netflix’s massive and fast-growing content budget, which the company estimates will be $7 billion for 2018. Financial analyst firm MoffettNathanson recently calculated Netflix is in fifth place in overall spending across film and TV — far behind traditional U.S. TV players NBCUniversal, Fox, Disney and Time Warner, but ahead of CBS, Amazon, Hulu, Facebook and Apple.

When it comes to non-sports TV programming expense alone, however, Netflix is very much in the top tier, coming in second, behind only NBCU. Yet Netflix’s revenue in the U.S. is still just a fraction of those of its major competitors. Even in just the TV business, NBCU, Fox and Disney are each roughly twice Netflix’s size, which allows them to spread that programming expense across a much larger revenue base.

How, then, can Netflix sustain its current level of spending on content and remain competitive? The secret lies in its international growth, something the big U.S. TV companies can’t tap into nearly as effectively.

Based on each company’s 10-K filing for the most recent fiscal year, only one of the traditional TV companies — Discovery — has a more even balance of domestic and international revenue than Netflix; the vast majority are significantly more U.S.-skewed.

Bear in mind, too, that most of these companies generate more international revenue from their film units than from their TV units, so their programming expenses for television are in many cases very U.S.-centric.

Netflix is also by far the fastest-moving company when it comes to globalization: Its international share of streaming revenue was just 10% five years ago, but has risen to 41% in the past year. That balance will continue to shift, since the company’s base of subscribers is greater overseas than in the U.S.

Why does all this matter? Because Netflix’s content investment is increasingly international in nature — the company is filming projects overseas, producing foreign-language programs and then making them available in many of its markets around the world, allowing it to spread the cost of investment across its entire base of more than 100 million streaming subscribers rather than just the half that’s in the U.S.

Given that the entire traditional pay-TV universe in the States is less than 100 million subs, no TV company whose investment is primarily dedicated to the U.S. market can subsist on that audience. As such, Netflix can continue to grow spending on content above and beyond the levels of even the largest U.S.-centric player while amortizing that cost over its entire massive subscriber base.

That international edge is going to become even more important as traditional TV revenues decline in the U.S., leaving the legacy players scrambling to find new sources.

Jan Dawson is the founder and chief analyst at Jackdaw Research, an advisory firm for the consumer technology market.