The rise of unlimited mobile data plans, coupled with increasingly fierce price competition, is doing a number on wireless carriers’ revenues.
For the first time in 17 years, carriers’ quarterly revenue from data plans declined from the previous year, wireless market analyst Cherian Sharma noted in his report on results from the first three months of the year.
The “unlimited price war reached its inevitable apex with Verizon buckling under market intensity and offering unlimited,” Sharma wrote. “It has been seven years since all four operators offered unlimited (but limited) data pricing in the U.S.”
T-Mobile and Sprint brought back low cost unlimited plans last summer (though the plans do have some limits). That put increasing pressure on Verizon and AT&T, which came out with new and revised plans earlier this year. That’s been a boon for consumers even as it puts increasing pressure on the carriers’ networks, as well as their finances.
Get Data Sheet, Fortune’s technology newsletter.
In the stock market so far this year, shares of Verizon (vz) have lost 15%, AT&T’s (t) stock price is down 10%, and Sprint (s) has declined 6%. Only T-Mobile has gained in 2017, with its stock price up 15%.
T-Mobile (tmus) is the third-ranked carrier by customers, but it led almost every category of service growth in the quarter, including service revenue, total net-adds, regular monthly (or postpaid) net-adds, and postpaid phone net-adds, Sharma said.
The first quarter results results also showed changes in consumers wireless usage beyond phones, Sharma noted. Connected tablets declined for the first time, while the number of connected cars accounted for 50% of all devices added in a quarter for the first time.
Consumers are keeping their phones longer than ever. With the near-complete end of subsidized phone sales, consumers kept their phones an average of 2.7 years before upgrading.