Someone needs to ask Hillary after this primary is over if she would consider pushing the DNC to get rid of them, and partly help fund state's primaries.
I wonder what kind of cost we'd be looking at for say, Nevada or Washington to switch to primaries. Iowa would probably be a problem since they want to be "first" and having a caucus helps them get ahead of New Hampshire.
This site listed costs for the 2012 primaries, which should be Republican only costs unless there's still a cost for the Dems when the sitting president doesn't get primaried, I don't know for sure.
State Total Cost of Primary Average Cost/Voter
Texas $15,883,428.32 $1.57
Indiana $6,969,771.96 $2.24
Tennessee $4,577,041.57 $1.57
Oklahoma $2,933,104.00 $1.63
Idaho $2,840,471.00 $3.93
North Dakota $1,352,114.00 $3.39
It seems plausible for the DNC to raise money for the states that don't have primaries right now, but it would probably be decently expensive. Assuming ~$2M for low pop states, and ~$5M for mid pop states (probably low estimates), that'd be $56M for all caucus states to have primaries. That's a lot of money not going to potential down ticket races though