Hey, we manage pretty well to get people to fill out complicated paper forms to calculate their taxes, so certainly it's feasible to enforce laws despite the obvious practical impossibility of actually physically forcing everyone to obey them.
Yeah, that's what happens when you threaten them to deprive them of their freedom, to torture, and to murder them. Perhaps you are so civilized you resort to fines first, but what if they decide to not pay said fine? Are you going to put them in prison? What if they resist being mugged and kidnapped? How are you going to get them to prison if they resist? I suggest you search for many instances of the IRS shooting innocent people, they literally have armed squads for that purpose, they flashbang babies, etc.
Are you really surprised that most of them comply? What other choice do they have?
Are you sure that's the whole of the definition from the source you took it from? It looks suspiciously like a fragment of the definition on en.oxforddictionaries.com, omitting the part of the definition that is more general.
Yes. Consider a detailed blueprint for a physical weapon. Or information that make coordinated use of armed forces more efficient. Or blackmailing material.
If you want to have the argument that a "thing" can mean "information" I wish you all the luck in getting a partner that agrees with you. Personally it's both for me, depending on the occasion.