Taxes (and tax deductions) are generally one of the best ways to align incentives. If it's a binary condition then you have tons of derelict content that should really be public domain, but because of the big ticket well-maintained Disney content the laws are written to be "reasonable" for that content and it ends up unnecessary locking up all of the other content from the 1970s
The government isn’t some beast we have to appease. It’s us! If we want to reform copyright, we don’t need to bribe ourselves with a new tax.