For those curious, this hypothetical mission would take longer to get to Pluto than New Horizons because it wouldn't just be flying by, it would need time to set up a slower approach and enter into orbit around Pluto and give the lander time to collect the sample. It would also need enough fuel to then change trajectories and return to Earth, as well as all of the fuel for the lander. These types of sample return missions are very expensive, which is why there have not been many. There were a few somewhat famous ones to the moon in the 60s and 70s, one that collected solar wind particles (barely had to leave the Earth's neighborhood, no landing required), one that flew through the tail of a comet and collected dust (no landing required), and one by JAXA that retrieved a sample from an asteroid. It's ultimately cheaper to bring the science/instrumentation to the object than the other way around, and those are the types of missions that get funding. A rover is far more likely than a sample return mission, but even so I wouldn't put money on a return to Pluto in the very near future.
And we don't have the plutonium for the power anymore due to nuclear arms limitations. And investing a 30 year career into one mission is much to ask of a scientist. And if you don't make the mission an international treaty with concrete spending and mission statements, the congress 10 years out will cut your mission funding. And and and... sigh, It can be done if we have the will. But that is the case in most things, is it not? Also that Hauyabusa mission is a study is disaster engineering. Everything that could go wrong at some point did, yet they still were able to hit the earth's atmosphere and land in Australia, albeit a bit later than planned. This is the mission that the idea of "Never give up! Never Surrender!" was a real battle cry. And now they are trying to rescue the Venus orbiter with seat of the pants engineering as well. I feel bad that JAXA has had a string of bad luck, but watching them recover has been amazing.
Well, you need someone like Alan Stern. He invested his whole career into New Horizons and he is pretty much the only reason why it happened and became the success that it is and has been so far. You know, his son Jordan is about to start grad school... Unfortunately I don't think that he's up for following in his father's footsteps. He's a math major in undergrad rather than anything astronomy related. Understandable that he wanted the chance to prove himself on his own rather than live in his father's shadow. But my point is that we need someone with that kind of drive and determination to get a mission through. The type of person where no matter what happens they keep trying until they finish the job. Maybe whoever was in charge of the Hayabusa?