l receives its spending still relatively easy as a leftover from the high days of fundamental physics around the middle of the previous century
I don't think so. Receiving spending isn't easy, but quite a fight. The reason it is still financed is the result of excellent lobbying and PR.
Some colleagues here are working on an experiment which shall go to the ISS with a space shuttle. When after the accidents it was unsure if the experiment will get a flight, students were send to the US congress to directly convince representatives and senators.
Recently a laboratory in South Dakota managed to get a 7 million donation from a private person, just because he thought detecting neutrinos is cool.

When judging spending on particle physics one should as well consider, that a huge machinery will die and it is very difficult to reestablish it. If you stop research now, and in 200 years one would like to restart it, one would have to redo a lot of work and rebuild knowledge, which will be lost.

With ecologists its a special story. First I think that spending for ecologist projects and physics are not at all exclusionary. The spending on science is not so high that a bit more would do any damage to the society. But ecologists really are bad organised. When some astrophysicists had a project in the Adria (ANTARES, listen to high energy neutrinos) they asked some ecologists if they didn't want to participate and put some instruments on the chains to have long term Adria watching deeply under water. They hadn't and that is typical. In physics people usually come up with a huge number of projects once you have some type of large experiment.
Ecologists are not enough connected with each other to lobby for a big project. 300m really is peanuts for a developed world society with a yearly GDP of maybe 30 trillion.

The most important development of particle physics was html, and like this probably spin-offs really will exist in the future. If they are of such enormous reach is unclear, but for more specialised applications it will be good enough.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers