You are picking nits. To make each and every sandwich the chef individually acquires the ingredients consuming his resources and time to create each individual creation. Literal millennia of custom says that he has the unique privilege of deciding on the disposition of each creation and the same custom governs his agreement to purchase meat from the butcher and the butchers agreement to purchase animals from the farmer.
He is very clearly selling the finished product of his work and time. The same is true when a musician sells one a cd he is selling the literal finished product of his work when he sells it fixed in a physical form. All the old rules of commerce apply to that good. The same is even true of an mp3. He is selling you the work of his computer to transfer to your computer the bits required to reproduce his sound.
The problem is that ultimately this very traditional payment of goods and services which works so well with sandwiches starts to break down with cds and mp3s because one doesn't need to steal anything at all cut the creator out of the loop. If one likes one can simply make your own sandwich or give a copy of a song to a friend. As soon as you aren't doing business with the author he has no inherent privilege over your interaction. In order to forbid cutting him out of the loop you must grant him new privileges over others property that resemble traditional property not at all.
You can grant him the right to be the only one allowed to put meat between bread, patents, or you can grant him the right to be the only one to produce with their own materials sandwiches identical or nearly enough to his own recipes copyright. These are always restrictions on what other people can do with their own property because computers are already property with all the rights attached as sandwiches.
The framers in fact discussed the purpose of copyright not to secure the owners natural rights alike property but in hopes that it would on net benefit society.
"The Congress shall have Power... To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;"
The fact that it is inherently limited should give you the first clue that its not alike traditional property. If it was alike to a thing owned by you why would you by necessity be dispossessed of it. Originally in 14-28 years.
Jefferson spoke well and early against the very idea.
"Stable ownership is the gift of social law, and is given late in the progress of society. It would be curious then, if an idea, the fugitive fermentation of an individual brain, could, of natural right, be claimed in exclusive and stable property. If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea, which an individual may exclusively possess as long as he keeps it to himself; but the moment it is divulged, it forces itself into the possession of every one, and the receiver cannot dispossess himself of it. Its peculiar character, too, is that no one possesses the less, because every other possesses the whole of it. He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density in any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation. Inventions then cannot, in nature, be a subject of property."
It is equally clear that IP isn't alike natural property and that we must necessarily examine the bargain to ensure that it is best from societies perspective. Since copyright is a gift not a natural right we needn't feel bad if for example we restore say its original term. It wouldn't be a taking but rather a restoration of balance in privileges granted.