Electric cars.

Yeah we have a shitty version today of them, but the technology is from the 1830s and it got suppressed and banned in the 1940s.

Then in the 80s I think, some company made some, was forced by the USA Government to recall and destroy them.

It wasn't until Elon Musk paid the bribes and provided an electric car that was inferior to petrol that USA finally allowed the technology again.

That and China starting to develop their own.

Whenever a monopoly exists tech gets suppressed.

In that case it was the oil barrons behind it.