True. My only criticism of projects like ITER, NIF, etc. are that they are more academic than deliberate in achieving energy generation anytime this century. Granted, you have to work out the fusion part first, but then what? Do we wait another 50-100 years for the anointed project scientists to build a working power plant? We need tons of engineering going into this - now.
The ROI of fusion research is unimaginable if it ultimately works out. $20 billion _per year_ should be the least we could do. We should keep throwing ITER a bone _and_ triple whatever domestic (USA) programs we have currently. Get multiple projects in the pipeline, humanity cannot wait much longer.
Ending energy scarcity forever is _the_ most important thing humanity will have done up to this date. Wealth, poverty, hunger, and greed will have very little meaning when energy is virtually free. On the other hand, there is much political denial since it would certainly be a game changer for those in power.
The same effort that went into the Manhattan project, or the Apollo program should just be a given here. Being over-budget is rather meaningless; you could be over-budget by 10x, and I wouldn't bat an eye. The Manhattan project built multiple enormous facilities in parallel. Laying foundations for enrichment refineries that weren't even designed yet. That took some leap of faith.
You have to take a lot of false paths and then breakthroughs can happen unexpectedly. But we won't get there by not trying at all. Until it is proven to be impossible, the risk of dropping a few tens of billions a year to end energy scarcity forever is a reasonable gamble.