Don't downvote them! This is actually a good question! (and gives us a chance to talk about why we should pursue these things!)

It's also incredible difficult to answer! Can we define what it means? Direct or indirect?

=== Indirect (LHC) ===

Well one of the reasons the LHC was built was to find the Higgs. To do so, we had to invent a lot of shit along the way. Thing is, when you're pushing the bounds of human knowledge, you don't exactly have all the devices you need to measure and test everything. The WWW[0] is famously one of such "spin-offs" as we needed to connect scientists from around the globe to distribute the data from this project. Remember that it is an international project[1*]. There is also a lot about superconductors and refrigeration, both of which significantly contribute to modern medical devices. A lot for magnets, vacuum devices, and electronics, all of which have permeated into industry.

These scientific projects also are a big political effort and demonstrate good will and can be grounds for collaboration and building democracies. The hosting countries also have a lot to benefit from as direct collaboration happens there. Just think of the force of putting a bunch of very smart people in a room together, especially when they are experts in very different things. It's difficult to predict the direct revenue, but at such a cheap cost, even small innovations can easily end up covering the costs. Certainly the internet has more than paid for CERN, in the form of tax revenues to each country compared to the cost they give, not to mention benefit to the public (especially considering other indirect aspects).

=== Direct (LHC) ===

Maybe a bit harder. There's some slides here [2] that claim CERN nets 3.3bn for 1993 - 2038. You can find much more detail here[3] and another independent one here[4]. I'd just like to note [4]'s last line in their abstract:

  We conservatively estimate that there is around a 90% probability that benefits exceed costs, with an expected net present value of about 2.9 billion euro, not considering the unpredictable applications of scientific discovery.

That's unfortunately impossible to say. To make use of it technologically we're at least 50 years away, which is to say "who the fuck knows". But also remember the cost is almost nothing. If we speculate, it is not unreasonable that the technologies that could be enabled through the understanding of this science (and the requisite further knowledge we'll need) could be insurmountable. We're talking about understanding how mass works. So if we're ever going to invent things like inertial dampeners (which would make mass an irrelevant aspect of transportation), mass effect drives, gravity generators, and so on, knowledge of the Higgs would be essential. But don't hold your breath on seeing technologies any time soon.

Remember that we're playing the long game with science. It is good to think about short term, but never forget the long game. If you forget you may win battles but will lose the war.

=== Side Note About Money ===

The LHC is actually one way I like to think about the ultra billionaires (like Musk, Bezos, Gates types). The reason being that with that level of wealth we cannot ignore the effects of compound interest, as this plays a significant role. Let's take Bezos, the #2 on the list (behind Bernard Arnault) with $203.3B. We can ask, how many LHCs could Bezos make? We assume 10 years to build at 0.5B/yr and then 1B/yr to operate. We'll assume a 7% interest rate, compounded yearly, which means 14.231B/yr! So clearly Bezos is worth at least 14 LHCs! We could get more precision and actually compound, but the quick version gives us a sufficient lower bound to really put into perspective either the wealth of Bezos or how cheap the LHC is. However your want to frame it. FWIW, with the same lazy analysis we get Forbes top 10 as: Arnault @ 15.2 LHCs, Bezos @ 14.2 LHCs, Musk @ 13.72 LHCs, Zuckerberg @ 12.7 LHCs, Ellison @ 10.7 LHCs, Buffett @ 9.6 LHCs, Gates @ 9.2 LHCs, Page @ 9.1 LHCs, Ballmer @ 8.8 LHCs, and Brin @ 8.8 LHCs.

I'm just saying, we could afford a lot of LHCs...

[0] https://www.home.cern/science/computing/birth-web

[1*] I wanted to take a minute to mention the cost, so we can better guestimate the ROI. The project took 10 years to build and cost about $5bn and costs about $1bn/yr to operate, with Germany being the largest contributor and only contributing 21%[1^]. I'm not sure how it works, but the Federal budget is about 370B euros but total gov spending was 1.76T for 2021. That would be 0.065% of the federal budget or 0.014% of the total spending. Pretty fucking cheap if you ask me!

[1^] https://en.wikipedia.org/wiki/CERN#Participation_and_funding

[2] https://fcc-cdr.web.cern.ch/webkit/press_material/Brochure_A... (site: https://fcc.web.cern.ch/society)

[3] https://indico.cern.ch/event/760053/contributions/3152652/at...

[4] https://www.sciencedirect.com/science/article/abs/pii/S00401...