The electric vehicle revolution may be in trouble, with executives warning the transition is not going as smoothly as they had hoped.

Automakers around the world have set ambitious dates by which they want to have the transition to EVs complete, with many shooting for 2030 – 2035. Unfortunately, according to a report by Insider, the transition is not going very well, with many CEOs and execs concerned about the challenges ahead.

“As we get further into the transformation to EV, it’s a bit bumpy,” said GM CEO Mary Barra, one of the industry’s biggest proponents of a switch to EVs.

“This is a pretty brutal space,” said Mercedes-Benz CFO Harald Wilhelm on an analyst call. “I can hardly imagine the current status quo is fully sustainable for everybody.”

At this point, there are multiple issues impeding adoption, most notably range anxiety and cost. Unfortunately, cost is an issue for both buyer and automaker alike, with Honda and GM recently ending a collaboration to jointly develop affordable EVs.

“After studying this for a year, we decided that this would be difficult as a business, so at the moment we are ending development of an affordable EV,” said Honda CEO Toshihiro Mibe.

As Insider points out, the pullback from EVs is justifying Toyota Chairman Akio Toyoda’s well-known reservations regarding the feasibility of an all-electric transition.

“People are finally seeing reality,” Toyoda said.