Even if curiosity is a good goal completely separated from application, something I personally do not believe, than it is still worth wondering if the LHC and high-cost particle physics gives the most important knowledge per dollar spend.

I remember reading a book by E.O.Wilson, in which he mentioned that a total inventarisation of world biodiversity, including all organisms in the rainforests, would cost on the order of 300 million dollar, an amount  incredibly high for ecologists. But LHC spends several times such a number per yearly.

It seems to me LHC and fundamental physics in general receives its spending still relatively easy as a leftover from the high days of fundamental physics around the middle of the previous century, when the strangest avenues of fundamental research would quickly result in applications.

So, funding for large-scale physics is partially a thank-you for the field that lead to electronics and nuclear power, and partially a hope for more such gifts.