The current Hybrid technology appears to be in jeopardy of being overtaken by advances in ICE. However there is a new evolution of Hybrid technologies that could prove to be much better once critical mass of production and acceptance reduces manufacturing costs. Anything that gets away from using batteries is a plus!
Here's an article on the flywheel Hybrid advances that is worth a read.
KERS of the hybrid car:Flywheels and ultracapacitors give you a 10-second jolt | ExtremeTech