Hybrid cars are still incredibly popular, but are they good for the environment?

A quarter century ago, Toyota unveiled a revolutionary vehicle: the Prius.

The Prius was the first of a new category of cars, marrying an electric motor to a gasoline engine to dramatically increase fuel economy and reduce emissions.

Today, hybrid vehicles remain popular with many drivers — enduringly popular, across a growing number of vehicle segments. That's even as a new revolution is unfolding, with automakers investing many billions of dollars in all-electric vehicles, which don't use gas at all.

Car buyers still like hybrids because they can save on gas, and cut their carbon footprint without having to deal with range anxiety or the need to charge at home.

But even as hybrids go mainstream, they are losing traction among their original enthusiasts: Environmentalists.

Many say it's time for hybrids to fade