They subsidize R&D because there's a public benefit to things like pure math that's difficult to internalize which leads to under supply from the market.
They subsidize agriculture because of lobbying and self-defense considerations.
In both cases, the government identified an under supply due to a market failure, and they judged that the externalized benefit was sufficiently large and so they stepped in to fix it.
In the case of crypto, the market failure is simply that carbon is too cheap. So why not address the actual market failure with a tax. If crypto miners want to keep mining after compensating society for their pollution, more power to them. It's hubris and risky to outright ban something because you just know there's no value there and all the people who ascribe value are wrong. Doing that isn't even analogous to government actions in the two examples you raised. A carbon tax is more analogous (it's sort of like an inverse-subsidiy as per your Ag example).
I like the carbon tax avenue for other reasons too. It's a broad, one shot thing that will roughly aligns incentives across all industries at once. Not perfect but a very good correction that broadly applies.
"by all accounts, it slightly increases employment"
Not by all accounts. The literature is not straight forward in this way. If it is a null effect, I don't see that as an invalidation of econ 101, either. It could just be very inelastic for small changes in the minimum wage with elasticity picking up for larger changes (which nobody doubts would happen).
They subsidize agriculture because of lobbying and self-defense considerations.
In both cases, the government identified an under supply due to a market failure, and they judged that the externalized benefit was sufficiently large and so they stepped in to fix it.
In the case of crypto, the market failure is simply that carbon is too cheap. So why not address the actual market failure with a tax. If crypto miners want to keep mining after compensating society for their pollution, more power to them. It's hubris and risky to outright ban something because you just know there's no value there and all the people who ascribe value are wrong. Doing that isn't even analogous to government actions in the two examples you raised. A carbon tax is more analogous (it's sort of like an inverse-subsidiy as per your Ag example).
I like the carbon tax avenue for other reasons too. It's a broad, one shot thing that will roughly aligns incentives across all industries at once. Not perfect but a very good correction that broadly applies.
Not by all accounts. The literature is not straight forward in this way. If it is a null effect, I don't see that as an invalidation of econ 101, either. It could just be very inelastic for small changes in the minimum wage with elasticity picking up for larger changes (which nobody doubts would happen).