Just as there is a wide variety of plants, there is also a wide variety of different pollinators, not just bees. While honey bees and native bees might be better pollinators, partially because they are generalists and will visit a wide variety of flowers, there are also many other pollinators which are equally important. For instance, butterflies are better suited for pollinating longer, tubular shaped flowers because of their long tongue. The same principal applies to hummingbirds. (Just think of hibiscus flowers). Some pollinators visit only certain flowers, like the orchid bee. And, fascinatingly, there are even certain plants that can only be pollinated by a certain insect or animal. For instance, the ghost orchid (Dendrophylax lindenii) can only be pollinated by the giant sphinx moth, the only insect with a long enough tongue to reach the nectar.
Therefore, every pollinator has a purpose and is equally important to our environment!