There are several issues here:
Foremost is that folk have begun to equate science with the measures taken against Covid that in popular perception were not very good. Trying to sell a big science spend to people who equate science with incompetence & stupidity is challenging and as politicians need to get re-elected, funding what many voters see as rubbish is not going to be done lightly.
Next is that the phase space for detecting dark matter although not exhausted is heavily constrained. Dark matter may be as real as the ether & there are serious folk postulating alternatives that explain galactic rotation curves via other sources: mass that we can not see because of the limit vision constrained by the speed of light, other ideas suggest similar ideas but due to the bending of space time via known gravitational mass. Some of these ideas would cancel the Big Bang hypothesis. There are already James Webb observations of structures that are extremely unlikely to have been formed by the Big Bang.
After that comes concerns that the whole Standard model is no longer appropriate. It was never right, getting the baryon to photon ratio wrong by huge factors & anyhow all the various fixes have not worked.
String theory has not provided any practical tests & the energies where folk think it would apply will not be approached by the big ring collider, so that it may need to be parked & other approaches considered, suggesting wait & see for funding big experimental projects.
Also we now have AI looking at many of these problems, giving individual researchers access to knowledge that previously could not be acquired in a human life time. This could easily change everything.
Then there are the various scientific factions all wanting funding, climate scientists being one of the noisiest & one of the weakest given very regular changes to predictions and today a new satellite (Pace):
https://www.space.com/nasa-pace-spacex- ... ion-launchto measure particulates & that may change the climate models drastically.
The big ring looks like a hard sell just now.
Regards,