Article IV Section 3 -- "The Congress shall have power to dispose of and make all needful Rules and Regulations respecting the Territory or
other Property belonging to the United States; and nothing in this Constitution shall be so construed as to Prejudice any Claims of the United States, or of any particular State."
I'm not saying that the feds owning 80% of Nevada is a good thing. But the Constitution opens the door to the federal government owning enclaves within the states. Unless and until the scope of the Property Clause is defined, I don't foresee a substantial change in the amount of property controlled by the fedgov.
You have to go back to Article I, Section 8. The word "Property" is capitalized because it refers to a specific piece of land; namely the land that forts, arsenals and dockyards and whatever land needful buildings sit on.
The word "Territory" is capitalized because it refers to specific pieces of land such as Guam, Puerto Rico, and the U.S. Virgin Islands.