Why try to solve a problem we've already solved?

We’re confused as to why people keep insisting upon trying to solve problems that are already solved. One example might be that the cure for climate change is to make non-fossil fuel energy generation cheaper than fossil fuel. Arguably - and yes, we know about intermittency and so on - this has already been done, certainly many claim this has been done. Good, so, the problem is solved, what’s everyone arguing about?

Or, today’s example:

Entrepreneurs with new ideas for more productive and sustainable farming will be helped to join the industry under changes to agricultural policy in England, the government has promised.

Land will be made available for new farmers by offering existing ones a lump sum “exit payment” made up of the subsidies they would have received up to 2027.

The exit scheme and “additional support” for new farmers will be available from 2022. They are two elements of a fundamental change in public funding for farming that will be phased in over the next seven years.

The difficulty with getting into farming is that the land - a useful asset to have in order to be able to farm - to farm upon is expensive. This requires would be farmers to have vast piles of capital upon which they’re not going to make much return. The answer to this is to make farmland cheaper.

One reason why farmland is so expensive is the European Union’s insistence upon the single payment. If you have land you get money. As David Ricardo pointed out over 200 years ago such a rise in land rental, properly defined, will simply increase the value of the land itself. High agricultural land prices are driven by that method of subsidy.

We’ve left the EU, we’re abandoning that method of subsidy. Land prices will, ceteris paribus, fall. We have solved the problem of vast piles of capital which will gain little return being required to enter farming.

Given that the problem is solved then why do we have more plans to solve it?

Well, other than the usual political insistence that farmers are special people who deserve ever more of everyone elses’ money that is?