There's only so much money to go around. As much as we space enthusiasts would like to believe otherwise, there isn't a strong consensus for a big increase in science/space funding. I've read several reports that PKE costs were rising, as were PKE costs.

What would you be willing to sacrifice to pay for Europa Orbiter or PKE? Ultimately, that's the central question. Since we can't afford everything, to pay for those missions' rising costs, something else will have to get cut. It's very easy to cut someone else's budget to pay for your projects. Would you be willing to have your observatory's budget cut? If you aren't willing to have your budget cut, then why should you expect anyone else to sacrifice their budget to pay for PKE/Europa Orbiter?