Most features (especially those based on speeds and feeds) are a cat and mouse game. Apple puts out the new iPhone and it's faster than anything on the market. 6 months later, the highest end Samsung phone is slightly faster than the iPhone. And the iPhone won't get updated for another 6 months. At which point, the new iPhone will be fastest again.
To switch platforms in pursuit of which device happens to have the slight speed edge today, is totally stupid. Once you're invested in a platform, the cost of switching is huge. The platform someone is on would have to be seriously pissing them off before they should reasonably consider switching. And, some people do switch to Samsung. Some people are irked by some of Apple's design decisions. But, I doubt it's because for 6 months the iPhone is slightly behind in one speed metric.
Name a single iphone that had faster LTE speeds than samsung