These are projections made in 1976. They can be read as different project plans made at that time for different amounts of funding. For example, "if we follow the blue plan, it would require 9 billion (2012) US dollars of funding in 1982 (etc.) and we would achieve fusion by 1990."
The 1976 projection was that, assuming funding was kept at the level of 1976 (~1 billion a year), fusion would not be achieved in the foreseeable future. It further shows that actual funding has been below that level.
In short: Yes, getting fusion off the ground sooner would have required more money. Not "always more", but more than "we project no success" levels.
