There are tens of thousands of us still driving the field (with many open questions) forward.
They know exactly what they are searching for, read the paper. Esp. in QCD there's a lot still missing. Sea quarks, gluons.
But even on the astronomic level GR leaves the dark matter hole, which is a non-satisfactory explanation to many. Elegant yes, but certainly not proper.
I'd also prioritize manned exploration above particle physics, but I think they should continue and grow in tandem as I see no way of knowing exactly what the future of these endeavors holds, other than that there is a reasonable argument to be made that either could produce discoveries of tremendous value.
This is an extremely pessimistic view. Yes, we're almost certainly going to find something there, but that doesn't mean there's nothing before then. I'd bet a reasonably large sum of money that there's something before around 10TeV.
Also, this collider isn't looking for new particles so much as trying to improve our understanding of ones we know about already.
I wouldn't imagine that particle physics would be coming to an end until we had an experimentally proven model that explained all phenomena we can observe