Sprint (NYSE: S) and Verizon Wireless (NYSE: VZ) have changed their mind and in what is becoming a pretty common move will start allowing Wi-Fi as a common feature in its smartphone line-up. The two U.S. CDMA carriers held off for years, while both AT&T (NYSE: T) and T-Mobile USA encouraged their users to roam on to large Wi-Fi networks they own and operate.

Initially, Wi-Fi was looked at as a potential threat to the carrier, which wanted users to pay for data going over their own network. But now, as data plans have begun more prevalent, and users want to conduct heavy-bandwidth applications, Wi-Fi is considered more of a savior than a threat. It’s not clear if that’s what has taken Sprint and Verizon so long to cozy up to Wi-Fi. After all, CDMA handsets can be significantly more expensive compared to their GSM sisters, so it may just have come down to cost.