The field of Elon Musk has been promising shit for years, what do you think?

Well we definitely have a lot more Elon Musk now

To be fair, he has delivered a lot of (bull)shit

How SpaceX and Tesla patent new industrial scale techniques and technologies for any competitor to use is the bullcase for bringing the future forward faster. Lookup at Starlink.

Given that you can do a lot more research in different fields at the same time for the amount of money the next bigger particle accellerator would cost, the answer is very likely yes.

Ok, which field? How much money will be needed? What potential experiments are lined up in those fields that need money to go forward?

Particle physics has told us a lot about the base nature of our model and the affirmation of the standard model. The fruits of these labors still take decades to make their mark on our world.

And, we still are working on those other things at the same time too. It turns out with 8 billion people on the planet and modern technology we can get an absolute fuckload done at once.

Not a physicist, but I think building state of the art particle accelerators probably requires doing a lot of research in many different fields

There is no way to answer that - we have limited money/people/time. Whatever we fund - we will get whatever the returns are - but there is no way to know what we don't have because we didn't fund some other thing. Even if in a few years we fund that other thing - what we get out of those funds is influenced by the other things we already know and so whatever we get out of it also shows the results of the other research that we already have.

The only exception is if some research reveals nothing. Though this isn't a useful claim: "it doesn't work" still revealed something.