If copyrights and patents are property, then why don't copyright owners and patent holders pay a property tax?
In the US the federal government has no property taxes, usually that is a state tax. States vary but where I live property taxes are for real property which is essentially real estate. We also pay a tangible tax and an intangible tax. The tangible tax is for hard physical assets the company owns such as PC's, copiers, vehicles, etc. We also pay an intagible tax for intangible assets such as patents, trademarks, goodwill, etc. So we pay taxes on patents and copyrights but they aren't called property taxes, they are called intagible taxes. Every state probably has different rules, this is just how it works in Florida.
In essence companies do pay taxes for copyrights and patents, they just aren't called taxes, they are called fees. It can't cost anywhere near what the fees are to obtain and maintain a patent for a patent clerk to review an application.