It most certainly is, at least in the real world. The ISS has cost more than $150 billion so far. That's not "a joke", it's the GDP of a mid-size country. I very much do hope that everyone involved is asking themselves hard questions about whether this expense is justified by whatever has been gained in return. Science is not a magical la-la-land where people have the right to piss away truckloads of public money on projects they feel are important, simply by virtue of invoking vague platitudes about the "need for humanity to know".
There are an endless number of scientific projects all looking for resources to fund them. If (potential) gain isn't the right criterion for prioritization, then I don't know what is.