You can't put a price on energy independence in a free market economy. Energy independence is a military objective and a matter of national security. The costs are difficult to put in perspective.
Oil companies are subsidized to the tune of Billions of dollars an hour. Subsidizing fusion energy would merely be redirecting that money to the greater payoff.
This is not true.. 1 billion an hour is 8.76 trillion a year yet you say "billions" an hour which would make it at least 17.52 trillion a year which is basically the entire GDP of the us.
Certainly oil companies are subsidized but not "to the tune of" the entire US GDP.