The web already had solved that problem, even with bootstrap version 2. Surely apple provides primitives such as border-radius and gradients, which are enough to create an eye-catching button?
The level of skeuomorphic design never really hit the web the same as it was on iOS before version 7. Remember the pool table green felt and wood trim of Game Center? That sort of thing is probably extremely expensive to design and maintain for the wide range of screens offered by Apple products.