Not so much so. Many cellular towers still use copper T1/DS3 uplinks but even if they are fed by fiber you're still paying for a committed level of bandwidth from a provider. Your circuit may have a 1Gbit/sec capacity but it can be provisioned at any speed. If the cellular provider was previously paying for 100Mbit/sec of bandwidth and now they need 300Mbit/sec that's an expense of scale.