Performance mostly. But also even when made by various AAA studios, the resulting games often have this uncanny similar-ness to them. Personally i prefer in-house engines even if its just to maintain variety in the industry.
Also obligatory shout out to id tech for continuing to show off their engines with indiana jones.
The problem with wireless isn't speed anymore, its stability. For a lot of applications that's fine since buffering and whatnot hides any hiccups. but gaming for example is a nightmare on wireless still.