Integrating the curves is maybe $100 billion. And below a certain level of funding nothing can really be done (you can't build any reactor on $10 and a box of surplus paperclips the IRS donated from pity). The fact we actual got anywhere using the handful of "it's a start" research reactors like JET, which dates to 1984, that could get built is a testament to the scientists and engineers, not a indictment of the field.
Basically, if as much was spent on it as we spent on blowing up poor countries for no real reason (at least $2,000 billion, just for Afghanistan), we'd likely be onto the second or third generation. Or we'd have concluded decades ago that it really can't be done to a five-sigma certainty.
The cynic in me says there's a renewed push for it recently because China has 3 research reactors, the next one (CFETR) is designed to outperform ITER (which China is contributing to) and support research for DEMO (which is to say, it is or is very close to being designed for experimental power generation), and the US feels in danger of being beaten to it.
$500 worth of steroids may let me bench press 200lbs, but it doesn’t follow that with $50,000 I could lift my house.