Of course it was, but it was MUCH more difficult for them. It is disingenuous to pretend that Citizens United didn't exacerbate an already bad situation.
In reality, there were two historical moments that changed the timeline: 1) RFK's assassination, which allowed Nixon to become president and took us down the Dark Republican path that led to MAGA, and 2) The 1974 Tax Code re-write, that first baked Trickle Down Economics into the tax code, created the Oligarch class, and gave them the disposable money to fund political manipulation.