I think you just recited the history of your awareness of Softbank, which is very different from the actual company history and business.

Softbank didn't originate with Vodafone; it was already 25 years old and a sprawling conglomerate, well-known for many ventures, when it acquired the mobile operator.

Also, your chart doesn't fit your story. Softbank offered the iPhone in 2008 and the other carriers got it in 2012–2013, but that corresponds to a dip and then a very modest gain in the chart.