When T-Mobile’s chief executive went before Senate lawmakers this year to make the case for his company’s merger with Sprint, he argued the deal could help preserve U.S. dominance in high-tech wireless networks for smartphones and other devices.

“We’ll make sure America wins the global 5G race,” John Legere vowed. “5G will unlock capabilities that will fuel job creation and innovation well beyond what we have seen so far.”

T-Mobile is not the only carrier touting the amazing new capabilities of 5G, or fifth-generation data networks. The entire industry has spent much of the year marketing a dazzling future to consumers, one in which the successor to 4G LTE enables entirely new technologies, such as self-driving cars and remote medicine.

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Despite the hype, 5G is still a long way from becoming a reality for the majority of everyday Americans. As companies such as AT&T and Verizon trade barbs over which one technically arrived first to the technology, analysts say the first 5G-capable smartphones will not even arrive on the market until next year at the earliest. And with carriers largely switching on their 5G networks in select cities at first, it will take years for 5G to become as commonplace as 4G LTE is today.

“It’s encouraging to see American cellular providers really jumping out in the forefront and deploying aggressively these advanced networks which could have some real advantages for consumers,” said Glenn Derene, an editor at Consumer Reports. But Derene has little advice for shoppers who have asked him whether they should buy a 5G-capable phone. “When you look to the markets to see what a 5G phone is like, there aren’t any. Certainly, Consumer Reports can’t comment on how good these phones will be until we get them in our lab.”

In recent months, wireless carriers have made significant advances toward deploying 5G, though those achievements come with important caveats.

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In October, Verizon announced it had activated 5G service for customers in four cities. The product is not meant for use outside the home; instead, it is being offered as a stand-in for residential Internet service. Still, it is a potentially transformative offering — households with only one wired Internet provider might soon have an additional choice. But it is not “mobile data” in the way consumers tend to think of it.